A practical reference on collagen: what it is, how it behaves, what the literature reports, and where the honest uncertainties sit.
This page was last updated on 2025-11-10 and is reviewed periodically as new material appears.
Molecular weight distribution is a central quality attribute because it influences solubility, viscosity, foaming, and sensory properties. High-performance size-exclusion chromatography with refractive index or multi-angle light scattering detection can estimate average molecular weight and polydispersity. The degree of hydrolysis is sometimes measured by quantifying free amino groups with trinitrobenzenesulfonic acid or o-phthalaldehyde. Results depend on calibration standards and mobile-phase conditions, so method details matter when comparing certificates of analysis. Reported values are operational rather than absolute unless the method is fully validated.
Collagen peptides are hygroscopic and can cake or lose flowability when exposed to moisture. Typical storage is in sealed containers at ambient temperature, away from direct sunlight and strong odors. High humidity and prolonged heat may increase Maillard browning, off-odors, or microbial risk. Food-grade specifications commonly set limits for moisture, ash, heavy metals, and total plate count. Stability studies often monitor appearance, moisture, molecular mass profile, and microbial counts over defined intervals.
Collagen is a structural protein found in skin, bone, tendon, and cartilage, where it forms a triple helix of three polypeptide chains. The chains contain repeating Gly-X-Y sequences, with proline and hydroxyproline frequently occupying the X and Y positions. Collagen peptides are fragments produced by breaking these long chains through hydrolysis. These fragments vary in length and amino acid composition depending on the source and processing method, so the term covers a range of products rather than a single defined molecule.
Hydrolysis converts native collagen into shorter peptides and improves water solubility. Enzymatic treatment with proteases such as pepsin or alkaline proteases is common, though acid or thermal hydrolysis can also be used. The resulting molecular weight distribution typically ranges from about 2 to 10 kilodaltons. Gelatin is a related product formed by partial hydrolysis, but it retains the ability to gel in water. Collagen peptides undergo further breakdown and generally do not form gels.
| Property | Value | Notes |
|---|---|---|
| Typical storage temperature | 15–25 °C | Dry, sealed containers; avoid prolonged heat. |
| Moisture content | ≤10% | Lower moisture reduces caking and microbial risk. |
| Hydroxyproline content | 8–14% | Varies by source and hydrolysis; used as collagen marker. |
| Common analytical method | SEC-HPLC | Used for molecular mass profiling. |
| Microbial limit | <10^4 CFU/g | Typical food-grade target; exact limits vary by market. |
Glu-270 and Arg-127 play an important role in catalysis shown in Figure 2. Arg-127 acts to stabilize the carbonyl of the substrate that is bound to amino group of phenylalanine. Simultaneously, the water molecule coordinated to zinc is deprotonated by Glu-270 and interacts with the carbonyl stabilized by Arg-127. This creates an intermediate, shown in Figure 2, where the negatively charged oxygen is coordinated to zinc, and through unfavorable electrostatic interactions between Glu-270 and the ionized product facilitates the release of the product at the end of catalysis. In recent computational studies, the mechanism of catalysis is similar but the difference in mechanism is that deprotonated water molecule binds to the carbon of the carbonyl, whereas Figure 2 shows the hydroxyl group stays coordinated to zinc. Then proteolysis occurs and the water molecule is then introduced back into the active site to coordinate to zinc. Several studies have been conducted exploring the details of the bond between carboxypeptidase A and substrate and how this affects the rate of hydrolysis. In 1934, it was first discovered through kinetic experiments that, in order for substrate to bind, the peptide that is to be hydrolyzed must be adjacent to a terminal free hydroxyl group. Also, the rate of hydrolysis can be enhanced if the C-terminal residue is branched aliphatic or aromatic. However, if the substrate is a dipeptide with a free amino group, it undergoes hydrolysis slowly; this, however, can be avoided if the amino group is blocked by N-acylation.
==== United Arab Emirates ==== Seven & I Holdings announced in June 2014 that they had agreed a contract with Seven Emirates Investment LLC to open the first Middle Eastern 7-Eleven in Dubai, United Arab Emirates during the summer of 2015. The company also said that they had plans to open about 100 stores in the country by the end of 2017. The first store was opened in October 2015. The country has 13 stores as of January 2018, but as of the 2020s, 7-Eleven has shut down and is now absent in Dubai until further notice.
== Appearance and anatomy == This species can reach a length of 8.8 centimetres (3.5 in) TL. Male dwarf gouramis in the wild have diagonal stripes of alternating blue and red colors; females are a silvery color. Besides the difference in color, the sex can be determined by the dorsal fin. The male's dorsal fin is pointed, while the female's is rounded or curved. They carry touch-sensitive cells on their thread-like pelvic fins. Dwarf gouramis sold in fish stores may also be solid colors (e.g., powder blue dwarf gourami or red flame variety) which are nothing but captive bred color morphs of the same species. Similar to the archerfish, the dwarf gourami can project a stream of water from its mouth to hunt prey above the surface, to a maximum distance of ~5 cm.
Sources: en.wikipedia.org
Laboratory mice Dogs Big cats Horses Cattle Chickens Bananaquit Gyrfalcon Kermode bears Rock pocket mice Domestic rabbits Antarctic fur seals Mammoth A study on unrelated British and Irish individuals demonstrated that over 80% of people with red hair and/or fair skin that tan poorly have a dysfunctional variant of the MC1R gene. This is compared to less than 20% in people with brown or black hair, and less than 4% in people showing a good tanning response. Asp294His (rs1805009) is a single nucleotide polymorphism (SNP) in the MC1R gene and it is associated with red hair and light skin type. Other SNPs in the gene, Arg151Cys and Arg160Trp, are also associated with red hair. The Out-of-Africa model proposes that modern humans originated in Africa and migrated north to populate Europe and Asia. These migrants most likely had a functional MC1R variant and, accordingly, dark hair and skin as displayed by indigenous Africans today. As humans migrated north, the absence of high levels of solar radiation in northern Europe and Asia relaxed the selective pressure on active MC1R, allowing the gene to mutate into dysfunctional variants without reproductive penalty, then propagate by genetic drift. Studies show the MC1R Arg163Gln allele has a high frequency in East Asia and may be part of the evolution of light skin in East Asian populations. No evidence is known for positive selection of MC1R alleles in Europe and there is no evidence of an association between the emergence of dysfunctional variants of MC1R and the evolution of light skin in European populations.
=== Flavin-independent ene-reductases === Flavin-independent ERs are able to reduce their substrates directly using the NAD(P)H cofactor that can be regenerated. Two families of this group are the medium-chain dehydrogenases/reductases (MDR; EC 1.3.1), and the short-chain dehydrogenases/reductases (SDR; EC 1.1.1.207−8). The typical substrates reduced by those enzymes include aromatic and monocyclic alkenes containing aldehydes or ketones as activating groups.
A thagomizer () is the distinctive arrangement of spike-shaped osteoderms on the tails of some stegosaurian dinosaurs. These spikes are believed to have been a defensive measure against predators. The arrangement of spikes originally had no distinct name. Cartoonist Gary Larson invented the name "thagomizer" in 1982 as a joke in his comic strip The Far Side, and it was gradually adopted as an informal term sometimes used within scientific circles, research, and education.
=== Onset and duration === The onset of action of psilocybin taken orally is 0.5 to 0.8 hours (30 to 50 minutes) on average, with a range of 0.1 to 1.5 hours (5 to 90 minutes). Peak psychoactive effects occur at about 1.0 to 2.2 hours (60 to 130 minutes). The time to offset of psilocybin orally is about 6 to 7 hours on average. The duration of action of psilocybin is about 4 to 6 hours (range 3–12 hours) orally. A small dose of 1 mg by intravenous injection had a duration of 15 to 30 minutes. In another study, 2 mg psilocybin by intravenous injection given over 60 seconds had an immediate onset, reached a sustained peak after 4 minutes, and subsided completely after 45 to 60 minutes.
Sources: en.wikipedia.org
Compounds and their metabolites need to be removed from the body via excretion, usually through the kidneys (urine) or in the feces. Unless excretion is complete, accumulation of foreign substances can adversely affect normal metabolism. There are three main sites where drug excretion occurs. The kidney is the most important site and it is where products are excreted through urine. Biliary excretion or fecal excretion is the process that initiates in the liver and passes through to the gut until the products are finally excreted along with waste products or feces. The last main method of excretion is through the lungs (e.g. anesthetic gases). Excretion of drugs by the kidney involves 3 main mechanisms:
One month later, the Phillips group independently reported the wild-type GFP structure in Nature Biotechnology. These crystal structures provided vital background on chromophore formation and neighboring residue interactions. Researchers have modified these residues by directed and random mutagenesis to produce the wide variety of GFP derivatives in use since then. Further research into GFP has shown that it is resistant to detergents, proteases, guanidinium chloride (GdmCl) treatments, and drastic temperature changes.
== Synthesis == The biosynthesis of monoglycosylceramides requires a direct transfer of the carbohydrate moiety from a sugar-nucleotide, such as uridine 5-diphosphate(UDP)-galactose, or UDP-glucose to the ceramide unit. The glycosyl-transferase catalyzed reaction results in an inversion of the glycosidic bond stereochemistry, changing from α →β. Synthesis of galactosylceramide, and glucosylceramide occurs on the lumenal surface of the endoplasmic reticulum, and on the cytosolic side of the early Golgi membranes respectively.
== ISO 3300 – ISO 3649 == ISO 3300:1976 Photography — Processing chemicals — Specifications for anhydrous sodium thiosulfate [Withdrawn: replaced with ISO 10636] ISO 3301:1975 Statistical interpretation of data – Comparison of two means in the case of paired observations ISO 3302 Rubber — Tolerances for products ISO 3302-1:2014 Part 1: Dimensional tolerances ISO 3302-2:2008 Part 2: Geometrical tolerances ISO 3303 Rubber- or plastics-coated fabrics — Determination of bursting strength ISO 3303-1 Part 1: Steel-ball method ISO 3303-2 Part 2: Hydraulic method ISO 3304:1985 Plain end seamless precision steel tubes — Technical conditions for delivery [Withdrawn without replacement] ISO 3305:1985 Plain end welded precision steel tubes — Technical conditions for delivery [Withdrawn without replacement] ISO 3306:1985 Plain end as-welded and sized precision steel tubes — Technical conditions for delivery [Withdrawn without replacement] ISO 3307:1975 Information interchange – Representations of time of the day [Withdrawn: replaced by ISO 8601:1988] ISO 3308:2012 Routine analytical cigarette-smoking machine — Definitions and standard conditions ISO/IEC 3309:1993 Information technology — Telecommunications and information exchange between systems — High-level data link control (HDLC) procedures — Frame structure [Withdrawn: replaced by ISO/IEC 13239] ISO 3310 sieves — Technical requirements and testing ISO 3310-1:2016 Part 1: Test sieves of metal wire cloth ISO 3310-2:2013 Part 2: Test sieves of perforated metal plate ISO 3310-3:1990 Part 3: Test sieves of electroformed sheets ISO/TR 3311:1974 Plain end precision steel tubes, welded and seamless — General tables of dimensions and masses per unit length [Withdrawn: replaced by ISO 4200] ISO 3312:1987 Sintered metal materials and hardmetals — Determination of Young modulus ISO/TR 3313:2018 Measurement of fluid flow in closed conduits — Guidelines on the effects of flow pulsations on flow-measurement instruments ISO 3314:1975 Shell drills with taper bore (taper bore 1 : 30 (included)) with slot drive ISO 3315:2018 Assembly tools for screws and nuts — Driving parts for hand-operated square drive socket wrenches — Dimensions and tests ISO 3316:2018 Assembly tools for screws and nuts — Attachments for hand-operated square drive socket wrenches — Dimensions and tests ISO 3317:2015 Assembly tools for screws and nuts — Square drive adaptor with hexagon or cylindrical flat drive, for power socket wrenches ISO 3318:2016 Assembly tools for screws and nuts — Open-ended wrenches, box wrenches and combination wrenches — Maximum widths of heads ISO 3319 Guide for the use of ISO 2859 "Sampling procedures and tables for inspection by attributes" [Rejected draft] ISO 3320:2013 Fluid power systems and components — Cylinder bores and piston rod diameters and area ratios — Metric series ISO 3321:1975 Fluid power systems and components — Cylinder bores and piston rod diameters — Inch series [Withdrawn without replacement] ISO 3322:1985 Fluid power systems and components — Cylinders — Nominal pressures [Withdrawn without replacement] ISO 3323:1987 Aircraft — Hydraulic components — Marking to indicate fluid for which component is approved ISO 3324 Aircraft tyres and rims ISO 3324-1:2013 Part 1: Specifications [Withdrawn without replacement] ISO 3324-2:2013 Part 2: Part 2: Test methods for tyres [Withdrawn without replacement] ISO 3325:1996 Sintered metal materials, excluding hardmetals — Determination of transverse rupture strength ISO 3326:2013 Hardmetals — Determination of (the magnetization) coercivity [Withdrawn without replacement] ISO 3327:2009 Hardmetals — Determination of transverse rupture strength ISO 3328:1975 Nitric acid for industrial use — Determination of sulphate content — Method by reduction and titrimetry [Withdrawn without replacement] ISO 3329:1975 Ammonium nitrate for industrial use — Determination of content of sulphur compounds — Method by reduction and titrimetry [Withdrawn without replacement] ISO 3330:1975 Ammonium nitrate for industrial use — Determination of ammoniacal nitrogen content — Titrimetric method after distillation [Withdrawn without replacement] ISO 3331:1975 Ammonium nitrate for industrial use — Determination of total nitrogen content — Titrimetric method after distillation [Withdrawn without replacement] ISO 3332:1975 Ammonium sulphate for industrial use — Determination of ammoniacal nitrogen content — Titrimetric method after distillation [Withdrawn without replacement] ISO 3333:1975 Ammonium sulphate for industrial use — Determination of copper content — Zinc dibenzyldithiocarbamate photometric method [Withdrawn without replacement] ISO 3334:2006 Micrographics — ISO resolution test chart No. 2 — Description and use ISO 3335:1977 Extruded solid profiles in aluminium-zinc- magnesium alloy Al Zn4,5 Mg1 (7020) — Chemical composition and mechanical properties [Withdrawn: replaced with ISO 209-1] ISO 3336:1993 Dentistry — Synthetic polymer teeth [Withdrawn: replaced with ISO 22112] ISO 3337:2000 T-slot cutters with cylindrical shanks and with Morse taper shanks having tapped hole ISO 3338 Cylindrical shanks for milling cutters ISO 3338-1:1996 Part 1: Dimensional characteristics of plain cylindrical shanks ISO 3338-2:2013 Part 2: Dimensional characteristics of flatted cylindrical shanks ISO 3338-3:1996 Part 3: Dimensional characteristics of threaded shanks ISO 3339 Tractors and machinery for agriculture and forestry — Classification and terminology ISO 3339-0:1986 Part 0: Classification system and classification [Withdrawn without replacement] ISO 3340:1976 Fibre building boards — Determination of sand content ISO 3341:2000 Textile glass — Yarns — Determination of breaking force and breaking elongation ISO 3342:2011 Textile glass — Mats — Determination of tensile breaking force ISO 3343:2010 Reinforcement yarns — Determination of twist balance index ISO 3344:1997 Reinforcement products — Determination of moisture content ISO 3345:1975 Wood — Determination of ultimate tensile stress parallel to grain [Withdrawn: replaced with ISO 13061-6] ISO 3346:1975 Wood — Determination of ultimate tensile stress perpendicular to grain [Withdrawn: replaced with ISO 13061-7] ISO 3347:1976 Wood — Determination of ultimate shearing stress parallel to grain [Withdrawn: replaced with ISO 13061-8] ISO 3348:1975 Wood — Determination of impact bending strength [Withdrawn: replaced with ISO 13061-10] ISO 3349:1975 Wood — Determination of modulus of elasticity in static bending [Withdrawn: replaced with ISO 13061-4] ISO 3350:1975 Wood — Determination of static hardness [Withdrawn: replaced with ISO 13061-12] ISO 3351:1975 Wood — Determination of resistance to impact indentation [Withdrawn: replaced with ISO 13061-11] ISO/TR 3352:1974 Acoustics — Assessment of noise with respect to its effect on the intelligibility of speech [Withdrawn without replacement] ISO 3353 Aerospace — Lead and runout threads ISO 3353-1:2020 Part 1: Rolled external threads ISO 3353-2:2020 Part 2: Internal threads ISO 3354:2008 Measurement of clean water flow in closed conduits – Velocity-area method using current-meters in full conduits and under regular flow conditions ISO 3355:1975 Shoe sizes — System of length grading (for use in the Mondopoint system) [Withdrawn: replaced with ISO 9407] ISO 3356:2009 Milk — Determination of alkaline phosphatase ISO 3357:1975 Sodium tripolyphosphate and sodium pyrophosphate for industrial use — Determination of total phosphorus(V) oxide content — Quinoline phosphomolybdate gravimetric method ISO 3358:1979 Sodium tripolyphosphate and sodium pyrophosphate for industrial use — Separation by column chromatography and determination of the different phosphate forms [Withdrawn without replacement] ISO 3359:1975 Phosphoric acid for industrial use — Determination of arsenic content — Silver diethyldithiocarbamate photometric method [Withdrawn without replacement] ISO 3360:1976 Phosphoric acid and sodium phosphates for industrial use (including foodstuffs) — Determination of fluorine content — Alizarin complexone and lanthanum nitrate photometric method ISO 3361:1975 Phosphoric acid for industrial use — Determination of soluble silica content — Reduced molybdosilicate spectrophotometric method [Withdrawn without replacement] ISO 3362:1976 Benzyl chloride for industrial use — Methods of test [Withdrawn without replacement] ISO 3363:1976 Fluorochlorinated hydrocarbons for industrial use — Determination of acidity — Titrimetric method ISO 3364:2017 Indexable hardmetal (carbide) inserts with rounded corners, with cylindrical fixing hole — Dimensions ISO 3365:2016 Indexable hardmetal (carbide) inserts with wiper edges, without fixing hole — Dimensions ISO 3366:1999 Coated abrasives — Abrasive rolls ISO 3367:1975 Coated abrasives — Rolls for widths of 50 mm and greater — Any backing — Designation and dimensions [Withdrawn: replaced with ISO 3366] ISO 3368:1975 Coated abrasives — Cloth rolls up to and including 40 mm width — Designation and dimensions [Withdrawn: replaced with ISO 3366] ISO 3369:2006 Impermeable sintered metal materials and hardmetals — Determination of density ISO 3371:1975 Modular units for machine tool construction — Rotary tables and multi-sided centre bases for rotary tables ISO 3372:1975 Shipbuilding — Inland vessels — Mushroom-type ventilator heads [Withdrawn without replacement] ISO 3373 Fibre building boards — Determination of paint absorption [Rejected draft] ISO 3374:2000 Reinforcement products — Mats and fabrics — Determination of mass per unit area ISO 3375:2009 Textile glass — Determination of stiffness of rovings ISO 3376:2020 Leather — Physical and mechanical tests — Determination of tensile strength and percentage elongation ISO 3377 Leather — Physical and mechanical tests — Determination of tear load ISO 3377-1:2011 Part 1: Single edge tear ISO 3377-2:2016 Part 2: Double edge tear ISO 3378:2002 Leather — Physical and mechanical tests — Determination of resistance to grain cracking and grain crack index ISO 3379:2015 Leather — Determination of distension and strength of surface (Ball burst method) ISO 3380:2015 Leather — Physical and mechanical tests — Determination of shrinkage temperature up to 100 °C ISO 3381:2021 Railway applications – Acoustics – Noise measurement inside railbound vehicles ISO 3382 Acoustics — Measurement of room acoustic parameters ISO 3382-1:2009 Acoustics — Measurement of room acoustic parameters — Part 1: Performance spaces ISO 3382-2:2008 Acoustics — Measurement of room acoustic parameters — Part 2: Reverberation time in ordinary rooms ISO 3382-3:2022 Acoustics — Measurement of room acoustic parameters — Part 3: Open plan offices ISO 3383:1985 Rubber — General directions for achieving elevated or subnormal temperatures for test purposes [Withdrawn: replaced with ISO 23529] ISO 3384 Rubber, vulcanized or thermoplastic — Determination of stress relaxation in compression ISO 3384-1:2019 Part 1: Testing at constant temperature ISO 3384-2:2019 Part 2: Testing with temperature cycling ISO 3385:2014 Flexible cellular polymeric materials — Determination of fatigue by constant-load pounding ISO 3386 Polymeric materials, cellular flexible — Determination of stress-strain characteristics in compression ISO 3386-1:1986 Part 1: Low-density materials ISO 3386-2:1997 Part 2: High-density materials ISO 3387:2020 Rubber — Determination of crystallization effects by hardness measurements ISO 3388:1977 Patent documents — Bibliographic references — Essential and complementary elements [Withdrawn: replaced with ISO 690] ISO 3389:1975 Aircraft — Radio frequency flexible coaxial cables — Dimensions and electrical characteristics [Withdrawn without replacement] ISO 3390:1976 Aluminium oxide primarily used for the production of aluminium — Determination of manganese content — Flame atomic absorption method [Withdrawn without replacement] ISO 3391:1976 Cryolite, natural and artificial — Determination of calcium content — Flame atomic absorption method ISO 3392:1976 Cryolite, natural and artificial, and aluminium fluoride for industrial use — Determination of water content — Electrometric method [Withdrawn without replacement] ISO 3393:1976 Cryolite, natural and artificial, and aluminium fluoride for industrial use — Determination of moisture content — Gravimetric method ISO 3394:2012 Packaging – Complete, filled transport packages and unit loads – Dimensions of rigid rectangular packages ISO 3395:1975 Rotary drilling equipment — Roller bits and blade drag bits [Withdrawn without replacement] ISO 3396:1975 Rotary drilling equipment — Diamond drilling bits and diamond core bits [Withdrawn without replacement] ISO 3397:1977 Broadleaved wood raw parquet blocks — General characteristics [Withdrawn: replaced with ISO 4556] ISO 3398:1977 Broadleaved wood raw parquet blocks — Classification of oak parquet blocks [Withdrawn: replaced with ISO 4561] ISO 3399:1976 Broadleaved wood raw parquet blocks — Classification of beech parquet blocks [Withdrawn: replaced with ISO 4561] ISO 3400:1997 Cigarettes — Determination of alkaloids in smoke condensates — Spectrometric method ISO 3401:1991 Cigarettes — Determination of alkaloid retention by the filters — Spectrometric method ISO 3402:1999 Tobacco and tobacco products — Atmosphere for conditioning and testing ISO 3405:2019 Petroleum and related products from natural or synthetic sources — Determination of distillation characteristics at atmospheric pressure ISO 3406:1975 Tobacco and tobacco products — Expression of analytical test results [Withdrawn without replacement] ISO 3407:1983 Information processing – Information interchange on 3,81 mm (0.150 in) magnetic tape cassette at 4 cpmm (100 cpi), phase encoded at 63 ftpmm (1 600 ftpi) [Withdrawn without replacement] ISO 3408 Ball screws ISO 3408-1:2006 Part 1: Vocabulary and designation ISO 3408-2:2021 Part 2: Nominal diameters, leads, nut dimensions and mounting bolts — Metric series ISO 3408-3:2006 Part 3: Acceptance conditions and acceptance tests ISO 3408-4:2006 Part 4: Static axial rigidity ISO 3408-5:2006 Part 5: Static and dynamic axial load ratings and operational life ISO 3409:1975 Passenger cars — Lateral spacing of foot controls ISO 3410:1989 Agricultural machinery — Endless variable-speed V-belts and groove sections of corresponding pulleys ISO 3411:2007 Earth-moving machinery — Physical dimensions of operators and minimum operator space envelope ISO 3412:1992 Road vehicles — Screened and waterproof spark-plugs and their connections — Types 1A and 1B ISO 3413:1975 Information processing — Recorded magnetic tapes for interchange instrumentation applications — Standard tape speeds and track configurations [Withdrawn: replaced with ISO 6068] ISO 3414 Modular coordination — co-ordinating sizes for windows [Rejected draft] ISO 3415:1986 Textile floor coverings — Determination of thickness loss after brief, moderate static loading ISO 3416:1986 Textile floor coverings — Determination of thickness loss after prolonged, heavy static loading ISO 3417:2008 Rubber — Measurement of vulcanization characteristics with the oscillating disc curemeter [Withdrawn: replaced with ISO 6502-2] ISO 3418:1975 Steel Tubes — Butt-welding bends, types 3D and 5D (45°, 90°, and 180°), without quality requirements [Withdrawn without replacement] ISO 3419:1981 Non-alloy and alloy steel butt-welding fittings ISO 3420:1975 Ammonium hydrogen carbonate for industrial use (including foodstuffs) — Determination of ash — Gravimetric method [Withdrawn without replacement] ISO 3421:2022 Petroleum and natural gas industries — Drilling and production equipment — Offshore conductor design, setting depth and installation [original draft related to Ammonium hydrogen carbonate for industrial use] ISO 3422:1975 Ammonium hydrogen carbonate for industrial use (including foodstuffs) — Determination of total carbon dioxide content — Titrimetric method [Withdrawn without replacement] ISO 3423:1975 Sulphuric acid and oleums for industrial use — Determination of sulphur dioxide content — Iodometric method ISO 3424:1975 Sodium perborates for industrial use — Determination of bulk density [Withdrawn without replacement] ISO 3425:1975 Sulphur for industrial use — Determination of ash at 850-900 degrees C and of residue at 200 degrees C ISO 3426:1975 Sulphur for industrial use — Determination of loss in mass at 80 degrees C ISO 3427:1976 Gaseous halogenated hydrocarbons (liquefied gases) — Taking of a sample ISO 3428:1976 Sodium fluoride for industrial use — Preparation and storage of test samples [Withdrawn without replacement] ISO 3429:1976 Sodium fluoride primarily used for the production of aluminium — Determination of iron content — 1,10- Phenanthroline photometric method ISO 3430:1976 Sodium fluoride primarily used for the production of aluminium — Determination of silica content — Reduced molybdosilicate spectrophotometric method ISO 3431:1976 Sodium fluoride primarily used for the production of aluminium — Determination of soluble sulphates content — Turbidimetric method ISO 3432:2008 Cheese — Determination of fat content — Butyrometer for Van Gulik method ISO 3433:2008 Cheese — Determination of fat content — Van Gulik method ISO 3434:2012 Ships and marine technology — Heated glass panes for ships' rectangular windows ISO 3435:1977 Continuous mechanical handling equipment — Classification and symbolization of bulk materials ISO 3437:1975 Road vehicles — Determination of fuel leakage in the event of a collision [Withdrawn without replacement] ISO 3438:2013 Subland twist drills for holes prior to tapping screw threads (originally Subland twist drills with Morse taper shanks for holes prior to tapping screw threads) ISO 3439:2003 Subland twist drills with cylindrical shanks for holes prior to tapping screw threads [Withdrawn: replaced with ISO 3438] ISO 3440 Twist drills with indexable inserts made of cemented carbide, with parallel shank, for metal and plastics [Rejected draft] ISO 3441 Twist drills with indexable inserts made of cemented carbide, with Morse taper shank, for metal and plastics [Rejected draft] ISO 3442 Machine tools — Dimensions and geometric tests for self-centring chucks with two-piece jaws ISO 3442-1:2005 Part 1: Manually operated chucks with tongue and groove type jaws ISO 3442-2:2005 Part 2: Power-operated chucks with tongue and groove type jaws ISO 3442-3:2007 Part 3: Power-operated chucks with serrated jaws ISO 3443 Tolerances for building ISO 3443-1:1979 Part 1: Basic principles for evaluation and specification ISO 3443-2:1979 Part 2: Statistical basis for predicting fit between components having a normal distribution of sizes ISO 3443-3:1987 Part 3: Procedures for selecting target size and predicting fit ISO 3443-4:1986 Part 4: Method for predicting deviations of assemblies and for allocation of tolerances ISO 3443-5:1982 Part 5: Series of values to be used for specification of tolerances ISO 3443-6:1986 Part 6: General principles for approval criteria, control of conformity with dimensional tolerance specifications and statistical control — Method 1 ISO 3443-7:1988 Part 7: General principles for approval criteria, control of conformity with dimensional tolerance specifications and statistical control — Method 2 (Statistical control method) ISO 3443-8:1989 Part 8: Dimensional inspection and control of construction work ISO 3444:2023 Stainless-steel wire ropes [original draft was Paper and board – Determination of abrasion resistance – Taber method] ISO/IEC TR 3445:2022 Information technology – Cloud computing – Audit of cloud services [original draft was Modular coordination — Preferred sizes for horizontal controlling dimensions] ISO 3446 Timber Structures – Determination of characteristic values of sawn timber from tests on Small Clear Wood Specimens [Under development; original draft was Modular coordination — Preferred sizes for vertical controlling dimensions] ISO 3447:1975 Joints in building — General check-list of joint functions ISO 3448:1992 Industrial liquid lubricants — ISO viscosity classification ISO 3449:2005 Earth-moving machinery — Falling-object protective structures — Laboratory tests and performance requirements ISO 3450:2011 Earth-moving machinery — Wheeled or high-speed rubber-tracked machines — Performance requirements and test procedures for brake systems ISO 3451 Plastics — Determination of ash ISO 3451-1:2019 Part 1: General methods ISO 3451-2:1998 Part 2: Poly(alkylene terephthalate) materials ISO 3451-3:1984 Part 3: Unplasticized cellulose acetate ISO 3451-4:1998 Part 4: Polyamides ISO 3451-5:2002 Part 5: Poly(vinyl chloride) ISO 3452 Non-destructive testing — Penetrant testing ISO 3452-1:2021 Part 1: General principles ISO 3452-2:2021 Part 2: Testing of penetrant materials ISO 3452-3:2013 Part 3: Reference test blocks ISO 3452-4:1998 Part 4: Equipment ISO 3452-5:2008 Part 5: Penetrant testing at temperatures higher than 50 degrees C ISO 3452-6:2008 Part 6: Penetrant testing at temperatures lower than 10 degrees C ISO 3453:1984 Non-destructive testing — Liquid penetrant inspection — Means of verification [Withdrawn without replacement] ISO 3454:2008 Hydrometry – Direct depth sounding and suspension equipment ISO 3455:2021 Hydrometry – Calibration of current-meters in straight open tanks ISO 3456:1975 Aircraft — Lever-operated manual switches (Class 3) — Performance requirements ISO 3457:2003 Earth-moving machinery — Guards — Definitions and requirements ISO 3458:2015 Plastics piping systems — Mechanical joints between fittings and pressure pipes — Test method for leaktightness under internal pressure ISO 3459:2015 Plastic piping systems — Mechanical joints between fittings and pressure pipes — Test method for leaktightness under negative pressure ISO 3460:1975 Unplasticized polyvinyl chloride (PVC) pressures pipes — Metric series — Dimensions of adapter for backing flange [Withdrawn: replaced with ISO 1452-3] ISO 3461 General principles for the creation of graphical symbols ISO 3461-1:1988 Part 1: Graphical symbols for use on equipment [Withdrawn: replaced with ISO 80416-1] ISO 3461-2:1987 Part 2: Graphical symbols for use in technical product documentation [Withdrawn: replaced with ISO 80416-1] ISO 3462:1980 Tractors and machinery for agriculture and forestry — Seat reference point — Method of determination [Withdrawn without replacement] ISO 3463:2006 Tractors for agriculture and forestry — Roll-over protective structures (ROPS) — Dynamic test method and acceptance conditions ISO 3464:1977 Textile machinery and accessories — Bearings for bottom rollers and allied dimensions — Caps with central nose and caps with side lugs [Withdrawn without replacement] ISO 3465:1975 Hand taper pin reamers ISO 3466:2016 Machine taper pin reamers with parallel shanks ISO 3467:2016 Machine taper pin reamers with Morse taper shanks ISO 3468:2014 Passenger cars — Windscreen defrosting and demisting systems — Test method ISO 3469:1989 Passenger cars — Windscreen washing systems — Test methods ISO 3470:1989 Passenger cars — Windscreen demisting systems — Test method [Withdrawn: replaced with ISO 3468] ISO 3471:2008 Earth-moving machinery — Roll-over protective structures — Laboratory tests and performance requirements ISO 3472:1975 Unplasticized polyvinyl chloride (PVC) pipes — Specification and determination of resistance to acetone [Withdrawn without replacement] ISO 3473:1977 Unplasticized polyvinyl chloride (PVC) pipes — Effect of sulphuric acid — Requirement and test method [Withdrawn without replacement] ISO 3474:1976 Unplasticized polyvinyl chloride (PVC) pipes — Specification and measurement of opacity [Withdrawn without replacement] ISO 3475:2020 Essential oil of aniseed (Pimpinella anisum L.) ISO 3476:1975 Modular units for machine tool construction — Tenon drive and flanges for mounting multi- spindle heads ISO 3477:1981 Polypropylene (PP) pipes and fittings — Density — Determination and specification [Withdrawn without replacement] ISO 3478:1975 Polypropylene (PP) pipes — Determination of longitudinal reversion [Withdrawn: replaced with ISO 2505-(1-2)] ISO 3480:1976 Polypropylene (PP) pipes — Maximum permissible longitudinal reversion [Withdrawn without replacement] ISO 3481 Acoustics — measurement of noise emitted by pneumatric tools and machines [Rejected draft] ISO 3482:2022 Marine technology — Technical guidelines for the active source exploration with Ocean Bottom Seismometers (OBS) [original draft with this number unknown] ISO 3483:2023 Copper and zinc sulfide concentrates — Determination of thallium — Acid digestion and inductively coupled plasma — mass spectrometry [original draft with this number unknown] ISO/TR 3485:1980 Plastics — Polypropylene granules — Determination of thermal stability in air by pH method [Withdrawn without replacement] ISO 3486:1980 Wrought copper and copper alloys — Cold-rolled flat products delivered in straight lengths (sheet) — Dimensions and tolerances [Withdrawn without replacement] ISO 3487:1980 Wrought copper and copper alloys — Cold-rolled flat products in coils or on reels (strip) — Dimensions and tolerances [Withdrawn without replacement] ISO 3488:1982 Wrought copper and copper alloys — Extruded round, square or hexagonal bars — Dimensions and tolerances [Withdrawn without replacement] ISO 3489:1984 Wrought copper and copper alloys — Drawn round bars — All minus tolerances on diameter and form tolerances [Withdrawn without replacement] ISO 3490:1984 Wrought copper and copper alloys — Drawn hexagonal bars — All minus tolerances on width across flats and form tolerances [Withdrawn without replacement] ISO 3491:1984 Wrought copper and copper alloys — Drawn square bars — All minus tolerances on width across flats and form tolerances [Withdrawn without replacement] ISO 3492:1982 Wrought copper and copper alloys — Drawn round wire — Tolerances on diameter [Withdrawn without replacement] ISO 3493:2014 Vanilla – Vocabulary ISO 3494:1976 Statistical interpretation of data – Power of tests relating to means and variances ISO 3495:1975 Dried milk — Determination of lactic acid and lactates content [Withdrawn: replaced with ISO 8069] ISO 3496:1994 Meat and meat products — Determination of hydroxyproline content ISO 3497:2000 Metallic coatings — Measurement of coating thickness — X-ray spectrometric methods ISO 3498:1979 Lubricants for machine tools — Classification [Withdrawn without replacement] ISO 3499:1976 Plastics — Aqueous dispersions of homopolymers and copolymers of vinyl acetate — Determination of bromine number [Withdrawn without replacement] ISO 3500:2005 Gas cylinders — Seamless steel CO2 cylinders for fixed fire-fighting installations on ships ISO 3501:2021 Plastics piping systems — Mechanical joints between fittings and pressure pipes — Test method for resistance to pull-out under constant longitudinal force ISO 3502 Mining – Building a reference architecture to support the evaluation of automation and autonomy solutions [Under development; original draft related to Plastics piping systems] ISO 3503:2015 Plastics piping systems — Mechanical joints between fittings and pressure pipes — Test method for leaktightness under internal pressure of assemblies subjected to bending ISO 3505:1975 Ropes and cordage — Equivalence between natural fibre ropes and man-made fibre ropes for use in the mooring of vessels ISO 3506 Mechanical properties of corrosion-resistant stainless steel fasteners ISO 3506-1:2020 Part 1: Bolts, screws and studs with specified grades and property classes ISO 3506-2:2020 Part 2: Nuts with specified grades and property classes ISO 3506-3:2009 Part 3: Set screws and similar fasteners not under tensile stress ISO 3506-4:2009 Part 4: Tapping screws ISO 3506-5:2022 Part 5: Special fasteners (also including fasteners from nickel alloys) for high temperature applications ISO 3506-6:2020 Part 6: General rules for the selection of stainless steels and nickel alloys for fasteners ISO 3507:1999 Laboratory glassware – Pyknometers ISO 3508:1976 Thread run-outs for fasteners with thread in accordance with ISO 261 and ISO 262 ISO 3509:2005 Coffee and coffee products – Vocabulary ISO/TR 3510 Advanced automated mining systems – Communication interface for interoperability between a supervisor system and heterogenous autonomous machine controllers [Under development; original draft with this nunber unknown] ISO 3511 Industrial process measurement control functions and instrumentation – Symbolic representation ISO 3511-1:1977 Part 1: Basic requirements [Withdrawn: replaced with ISO 14617-2:2025] ISO 3511-2:1984 Part 2: Extension of basic requirements [Withdrawn: replaced with ISO 14617-2:2025] ISO 3511-3:1984 Part 3: Detailed symbols for instrument interconnection diagrams [Withdrawn: replaced with ISO 14617-2:2025] ISO 3511-4:1985 Part 4: Basic symbols for process computer, interface, and shared display/control functions [Withdrawn: replaced with ISO 14617-2:2025] ISO 3512:1992 Heavy-duty cranked-link transmission chains ISO 3513:1995 Chillies — Determination of Scoville index ISO 3514:1976 Chlorinated polyvinyl chloride (CPVC) pipes and fittings — Specification and determination of density ISO 3515:2002 Oil of lavender (Lavandula angustifolia Mill.) ISO 3516:1997 Oil of coriander fruits (Coriandrum sativum L.) ISO 3517:2012 Essential oil of neroli (Citrus aurantium L., syn. Citrus amara Link, syn. Citrus bigaradia Loisel, syn. Citrus vulgaris Risso) ISO 3518:2002 Oil of sandalwood (Santalum album L.) ISO 3519:2005 Oil of lime distilled, Mexican type (Citrus aurantifolia (Christm.) Swingle) ISO 3520:2022 Oil of bergamot [Citrus aurantium L. subsp. bergamia (Wight et Arnott) Engler], Italian type ISO 3521:1997 Plastics — Unsaturated polyester and epoxy resins — Determination of overall volume shrinkage ISO 3522:2007 Aluminium and aluminium alloys — Castings — Chemical composition and mechanical properties ISO 3523:2002 Oil of cananga (Cananga odorata (Lam.) Hook. f. et Thomson, forma macrophylla) ISO 3524:2003 Oil of cinnamon leaf, Sri Lanka type (Cinnamomum zeylanicum Blume) ISO 3525:2008 Oil of amyris (Amyris balsamifera L.) ISO 3526:2005 Oil of sage, Spanish (Salvia lavandulifolia Vahl) ISO 3527:2016 Essential oil of parsley fruits (Petroselinum sativum Hoffm.) ISO 3528:2012 Essential oil of mandarin, Italian type (Citrus reticulata Blanco) ISO 3529 Vacuum technology – Vocabulary ISO 3529-1:2019 Part 1: General terms ISO 3529-2:2020 Part 2: Vacuum pumps and related terms ISO 3529-3:2024 Part 3: Total and partial pressure vacuum gauges ISO 3530:1979 Vacuum technology — Mass-spectrometer-type leak-detector calibration ISO 3531 Financial services — Financial information eXchange session layer [Original draft with this number unknown] ISO 3531-1:2022 Part 1: FIX tagvalue encoding ISO 3531-2:2022 Part 2: FIX session layer ISO 3531-3:2022 Part 3: FIX session layer test cases ISO 3532 Information technology — 3D Printing and scanning — Medical image-based modelling [Original draft with this number unknown] ISO 3532-1:2023 Part 1: General requirement ISO 3532-2:2024 Part 2: Segmentation ISO 3533:2021 Sex toys — Design and safety requirements for products in direct contact with genitalia, the anus, or both ISO 3534 Statistics – Vocabulary and symbols ISO 3534-1:2006 Part 1: General statistical terms and terms used in probability ISO 3534-2:2006 Part 2: Applied statistics ISO 3534-3:2013 Part 3: Design of experiments ISO 3534-4:2014 Part 4: Survey sampling ISO 3535:1977 Forms design sheet and layout chart [Withdrawn without replacement] ISO 3536:2016 Road vehicles – Safety glazing materials – Vocabulary ISO 3537:2015 Road vehicles – Safety glazing materials – Mechanical tests ISO 3538:1997 Road vehicles – Safety glazing materials – Test methods for optical properties ISO 3539:1975 Road vehicles — Injection nozzle holder with body, types 8 and 10, and injection nozzle holder with fixing flats, types 9 and 11 ISO 3540:1976 Paper or plastic printing ribbons – Characteristics of cores ISO 3541:1985 Earth-moving machinery — Dimensions of fuel filler opening [Withdrawn without replacement] ISO 3542:1975 Earth-moving machinery — Lubrication intervals [Withdrawn: replaced with ISO 6750] ISO 3543:2000 Metallic and non-metallic coatings — Measurement of thickness — Beta backscatter method ISO 3544:1978 Atomizing oil burners of the monobloc type — Safety times and safety control and monitoring devices [Withdrawn without replacement] ISO 3545 Steel tubes and fittings — Symbols for use in specifications ISO 3545-1:1989 Part 1: Tubes and tubular accessories with circular cross-section ISO 3545-2:1989 Part 2: Square and rectangular hollow sections ISO 3545-3:1989 Part 3: Tubular fittings with circular cross-section [Withdrawn without replacement] ISO 3546:1976 Fibre building boards — Determination of surface finish (roughness) [Withdrawn without replacement] ISO 3547 Plain bearings — Wrapped bushes ISO 3547-1:2018 Part 1: Dimensions ISO 3547-2:2017 Part 2: Test data for outside and inside diameters ISO 3547-3:2017 Part 3: Lubrication holes, grooves and indentations ISO 3547-4:2017 Part 4: Materials ISO 3547-5:2020 Part 5: Checking the outside diameter ISO 3547-6:2020 Part 6: Checking the inside diameter ISO 3547-7:2020 Part 7: Measurement of wall thickness of thin-walled bushes ISO 3548 Plain bearings — Thin-walled half bearings with or without flange ISO 3548-1:2022 Part 1: Tolerances, design features and methods of test ISO 3548-2:2020 Part 2: Measurement of wall thickness and flange thickness ISO 3548-3:2012 Part 3: Measurement of peripheral length ISO 3549:1995 Zinc dust pigments for paints — Specifications and test methods ISO 3550 Cigarettes — Determination of loss of tobacco from the ends ISO 3550-1:1997 Part 1: Method using a rotating cylindrical cage ISO 3550-2:1997 Part 2: Method using a rotating cubic box (sismelatophore) ISO 3551 Rotary core diamond drilling equipment — System A ISO 3551-1:1992 Part 1: Metric units ISO 3551-2:1992 Part 2: Inch units ISO 3552 Rotary core diamond drilling equipment — System B ISO 3552-1:1992 Part 1: Metric units ISO 3552-2:1992 Part 2: Inch units ISO 3553 Road vehicles — High-tension connections for ignition coils and distributors ISO 3553-1:1987 Part 1: Socket-type ISO 3553-2:1997 Part 2: Plug-types ISO 3554:1976 Credit cards — Magnetic stripe encoding for tracks 1 and 2 [Withdrawn: replaced with ISO 7810, ISO 7811-(1-5), and ISO/IEC 7813] ISO 3555:1977 Centrifugal, mixed flow and axial pumps — Code for acceptance tests — Class B [Withdrawn: replaced with ISO 9906] ISO 3556 Sputter-ion pumps — Measurement of performance characteristics [Rejected draft] ISO 3557 Plastics — Recommended Practice for Spectrophotometry and Calculation of Colour in CIE Systems [Rejected draft] ISO 3558 Plastics — Assessment of the Color of Near White or Near Colorless Materials [Rejected draft] ISO 3559:1976 Road vehicles — Working voltages for lights fitted to motor vehicles and to their trailers [Withdrawn without replacement] ISO 3560:2013 Road vehicles — Frontal fixed barrier or pole impact test procedure ISO 3561:1976 Information processing – Interchangeable magnetic six-disk pack – Track format [Withdrawn without replacement] ISO 3562:1976 Information processing – Interchangeable magnetic single-disk cartridge (top loaded) – Physical and magnetic characteristics [Withdrawn without replacement] ISO 3563:1976 Information processing – Interchangeable magnetic single-disk cartridge (top loaded) – Track format [Withdrawn without replacement] ISO 3564:1976 Information processing – Interchangeable magnetic eleven-disk pack – Physical and magnetic characteristics [Withdrawn without replacement] ISO 3565:1975 Meat and meat products — Detection of salmonellae (Reference method) [Withdrawn without replacement] ISO 3566:1976 Sodium fluoride primarily used for the production of aluminium — Determination of chlorides content — Turbidimetric method ISO 3567:2011 Vacuum gauges — Calibration by direct comparison with a reference gauge ISO 3568 Ionization vacuum gauges — Calibration by direct comparison with a reference gauge [Rejected draft] ISO 3569:1976 Continuous mechanical handling equipment — Classification of unit loads [Withdrawn without replacement] ISO 3570 Vacuum gauges — Standard methods for calibration [Rejected draft] ISO 3571 Passenger lift installations ISO 3571-1:1977 Part 1: Residential buildings – Definitions, functional dimensions, and modular co-ordination dimensions [Withdrawn: replaced by ISO 4190-1, in 2019 replaced by ISO 8100-30] ISO 3572:1976 Textiles – Weaves – Definitions of general terms and basic weaves ISO 3573:2012 Hot-rolled carbon steel sheet of commercial and drawing qualities ISO 3574:2012 Cold-reduced carbon steel sheet of commercial and drawing qualities ISO 3575:2016 Continuous hot-dip zinc-coated and zinc-iron alloy-coated carbon steel sheet of commercial and drawing qualities ISO 3576:1976 Hot-rolled carbon steel sheet coils for the production of cold-reduced products [Withdrawn without replacement] ISO 3577:1988 Animal fats — Determination of Bömer value [Withdrawn without replacement] ISO 3578:1980 Steel wire ropes — Standard designations [Withdrawn without replacement] ISO 3579 Technical Standard for Installation of Structural Modules in Nuclear Power Plants [rejected draft; original was Green coffee beans — Determination of mass of foreign matter which was incorporated into ISO 4149] ISO 3580:2017 Welding consumables — Covered electrodes for manual metal arc welding of creep-resisting steels — Classification ISO 3581:2016 Welding consumables — Covered electrodes for manual metal arc welding of stainless and heat-resisting steels — Classification ISO 3582:2000 Flexible cellular polymeric materials — Laboratory assessment of horizontal burning characteristics of small specimens subjected to a small flame ISO 3583:1984 Road vehicles — Pressure test connection for compressed-air pneumatic braking equipment ISO 3584:2020 Road vehicles — Clevis couplings — Interchangeability ISO 3585:1998 Borosilicate glass 3.3 — Properties ISO 3586:1976 Glass plant, pipeline and fittings — General rules for testing, handling and use [Withdrawn without replacement] ISO 3587:1976 Glass plant, pipeline and fittings — Pipeline and fittings of nominal bore 15 to 150 mm — Compatibility and interchangeability [Withdrawn without replacement] ISO 3588:1977 Spices and condiments — Determination of degree of fineness of grinding — Hand sieving method (Reference method) ISO 3589:1975 Modular units for machine tool construction — Integral way columns ISO 3590:1976 Modular units for machine tool construction — Spindle units ISO 3591:1977 Sensory analysis – Apparatus – Wine-tasting glass ISO 3592:2000 Industrial automation systems — Numerical control of machines — NC processor output — File structure and language format ISO 3593:1981 Starch — Determination of ash ISO 3594:1976 Milk fat — Detection of vegetable fat by gas-liquid chromatography of sterols (Reference method) [Withdrawn without replacement] ISO 3595:1976 Milk fat — Detection of vegetable fat by the phytosteryl acetate test ISO 3596:2000 Animal and vegetable fats and oils — Determination of unsaponifiable matter — Method using diethyl ether extraction ISO 3597 Textile-glass-reinforced plastics — Determination of mechanical properties on rods made of roving-reinforced resin ISO 3597-1:2003 Part 1: General considerations and preparation of rods ISO 3597-2:2003 Part 2: Determination of flexural strength ISO 3597-3:2003 Part 3: Determination of compressive strength ISO 3597-4:2003 Part 4: Determination of apparent interlaminar shear strength ISO 3598:2011 Textile glass — Yarns — Basis for a specification ISO 3599:1976 Vernier callipers reading to 0,1 and 0,05 mm [Withdrawn without replacement] ISO 3600:2015 Tractors, machinery for agriculture and forestry, powered lawn and garden equipment — Operator's manuals — Content and format ISO 3601 Fluid power systems – O-rings ISO 3601-1:2012 Inside diameters, cross-sections, tolerances and designation codes ISO 3601-2:2016 Housing dimensions for general applications ISO 3601-3:2005 Quality acceptance criteria ISO 3601-4:2008 Anti-extrusion rings (back-up rings) ISO 3601-5:2015 Suitability of elastomeric materials for industrial applications ISO 3602:1989 Documentation – Romanization of Japanese (kana script) ISO 3603:1977 Fittings for unplasticized polyvinyl chloride (PVC) pressure pipes with elastic sealing ring type joints — Pressure test for leakproofness ISO 3604:1976 Fittings for unplasticized polyvinyl chloride (PVC) pressure pipes with elastic sealing ring type joints — Pressure test for leakproofness under conditions of external hydraulic pressure [Withdrawn without replacement] ISO 3605:1987 Textile glass — Rovings — Determination of compressive strength of rod composites [Withdrawn: replaced with ISO 3597-3] ISO 3606:1976 Unplasticized polyvinyl chloride (PVC) pipes — Tolerances on outside diameters and wall thicknesses [Withdrawn: replaced with ISO 11922-(1-2)] ISO 3607:1977 Polyethylene (PE) pipes — Tolerances on outside diameters and wall thicknesses [Withdrawn: replaced with ISO 11922-(1-2)] ISO 3608:1976 Chlorinated polyvinyl chloride (CPVC) pipes — Tolerances on outside diameters and wall thicknesses [Withdrawn: replaced with ISO 11922-(1-2)] ISO 3609:1977 Polypropylene (PP) pipes — Tolerances on outside diameters and wall thicknesses [Withdrawn: replaced with ISO 11922-(1-2)] ISO 3610:1976 Modular units for machine tool construction — Support brackets ISO 3611:2010 Geometrical product specifications (GPS) – Dimensional measuring equipment: Micrometers for external measurements – Design and metrological characteristics ISO 3612:1977 Tobacco and tobacco products — Cigarettes — Determination of rate of free combustion [Withdrawn without replacement] ISO 3613:2021 Metallic and other inorganic coatings — Chromate conversion coatings on zinc, cadmium, aluminium-zinc alloys and zinc-aluminium alloys — Test methods ISO 3614:1975 Shipbuilding — Inland vessels — Detachable ladders [Withdrawn without replacement] ISO 3615:1976 Magnetic tape for instrumentation applications — Standardization of analogue modes of recording [Withdrawn: replaced with ISO 6068] ISO 3616:2001 Textile glass — Chopped-strand and continuous-filament mats — Determination of average thickness, thickness under load and recovery after compression ISO 3617:1994 Photography — Processing chemicals — Specifications for sodium hydroxide ISO 3618:1994 Photography — Processing chemicals — Specifications for benzotriazole ISO 3619:1994 Photography — Processing chemicals — Specifications for ammonium thiosulfate solution ISO 3620:1994 Photography — Processing chemicals — Specifications for aluminium potassium sulfate ISO 3621:1994 Photography — Processing chemicals — Specifications for sodium tetraborate decahydrate ISO 3622:1996 Photography — Processing chemicals — Specifications for ammonium thiocyanate ISO 3623:1994 Photography — Processing chemicals — Specifications for anhydrous potassium carbonate ISO 3624:1994 Photography — Processing chemicals — Specifications for potassium ferricyanide ISO 3625:1994 Photography — Processing chemicals — Specifications for potassium hydroxide ISO 3626:1996 Photography — Processing chemicals — Specifications for potassium thiocyanate ISO 3627:2001 Photography — Processing chemicals — Specifications for anhydrous sodium metabisulfite ISO 3628:1994 Photography — Processing chemicals — Specifications for boric acid, granular ISO 3629:2000 Photography — Processing chemicals — Specifications for potassium metabisulfite ISO 3630 Dentistry — Endodontic instruments ISO 3630-1:2019 Part 1: General requirements ISO 3630-2:2013 Part 2: Enlargers ISO 3630-3:2021 Part 3: Compactors ISO 3630-4:2009 Part 4: Auxiliary instruments ISO 3630-5:2020 Part 5: Shaping and cleaning instruments ISO 3630-6:2023 Part 6: Numeric coding system ISO 3630-7 Part 7: Ultrasonic inserts [Under development] ISO 3631:2019 Citrus fruits — Guidelines for storage ISO 3632 Spices – Saffron (Crocus sativus L.) ISO 3632-1:2011 Part 1: Specification ISO 3632-2:2010 Part 2: Test methods ISO 3633:2002 Plastics piping systems for soil and waste discharge (low and high temperature) inside buildings — Unplasticized poly(vinyl chloride) (PVC-U) ISO 3634:1979 Vegetable products — Determination of chloride content ISO 3635:1981 Size designation of clothes – Definitions and body measurement procedure [Withdrawn: replaced with ISO 8559-1] ISO 3636:1977 Size designation of clothes — Men's and boys' outerwear garments [Withdrawn: replaced with ISO 8559-2] ISO 3637:1977 Size designation of clothes — Women's and girls' outerwear garments [Withdrawn: replaced with ISO 8559-2] ISO 3638:1977 Size designation of clothes — Infants' garments [Withdrawn: replaced with ISO 8559-2] ISO 3639:1981 Cinematography — Projection reels/spools 75 to 312 mm diameter for 8 mm Type S motion-picture film — Dimensions and specifications ISO 3640:1982 Cinematography — Motion-picture prints and sound records for international exchange of television programmes — Specifications [Withdrawn without replacement] ISO 3641:1976 Cinematography — Motion-picture camera cartridge, 8 mm Type S Model II — Cartridge fit and take-up core drive — Dimensions and specifications ISO 3642:1983 Cinematography — Cemented or welded splices on 8 mm Type S motion-picture film for projector use — Dimensions ISO 3643:2024 Rolling bearings — Ceramic rolling elements — Terms and characteristics of surface imperfections [Original draft was Cinematography — Image area produced by 8 mm Type S Model II motion-picture camera aperture and maximum projectable image area — Positions and dimensions] ISO 3644:1976 Cinematography — Spindles for 8 mm Type R motion-picture cameras and projectors — Dimensions ISO 3645:1984 Cinematography — Image area produced by 8 mm Type S motion-picture camera aperture and maximum projectable image area — Positions and dimensions ISO 3646:1976 Cinematography — Motion-picture camera cartridge, 8 mm Type S Model II — Slots, projections and cartridge hole for indicating film speed, colour balance and film identification — Dimensions and positions ISO 3647:1976 Cinematography — Spindles for 16 mm motion-picture camera spools and projector reels — Dimensions ISO 3648:1994 Aviation fuels — Estimation of net specific energy ISO 3649:1980 Cleaning equipment for air or other gases — Vocabulary [Withdrawn: replaced with ISO 29464]
== Chemical properties == Alkanes are only weakly reactive with most chemical compounds. They only react with the strongest of electrophilic reagents by virtue of their strong C–H bonds (~100 kcal/mol) and C–C bonds (~90 kcal/mol). They are also relatively unreactive toward free radicals. This inertness is the source of the term paraffins (with the meaning here of "lacking affinity"). In crude oil the alkane molecules have remained chemically unchanged for millions of years.
Sources: en.wikipedia.org
Purity is assessed through a combination of protein content, hydroxyproline, amino acid composition, and chromatographic profile. Moisture, ash, and microbial tests cover non-protein impurities and handling quality.
Suppliers use different hydrolysis conditions, filtration steps, and analytical methods. Average molecular weight can also be calculated differently, so the distribution and method should be compared rather than a single number.
Store in a cool, dry place in tightly closed containers. Protect from moisture, heat, and strong odors; follow the supplier's labeled conditions for shelf life.
Collagen peptides are short chains of amino acids made by hydrolyzing native collagen. They are water-soluble and do not form gels like gelatin.