Quality standards

This method (see PDF) relates to “insoluble foreign matter” for detecting water-insoluble foreign matter.
Since high-quality amino acids are soluble in the right environment, insoluble foreign matter in the sample solution indicates the degree of microbial contamination of poor quality products.
As shown in the graph below, the amount of insolubles is strongly correlated with the frequency of bacterially contaminated samples.
The fewer insoluble particles, the easier it is to eliminate products that contain bacteria.
< 10 particles (size 1 x 1 mm) standard proposed by ICAAS eliminates 80% of low quality samples. The number of bacteria is usually counted by growing the bacteria on a plate. The proposed insoluble foreign matter test is easier and faster than the bacterial count method and can be used for all major amino acids listed below.

amino acid(th) Crystal form CAS registration number
L-alanine 56-41-7
L-Arginine 74-79-3
L-Arginine HCl 74-79-3
L-asparagine Monohydrate 5794–13-8
L-asparagine anhydrous 70-47-3
L-Aspartic acid 56-84-8
L-cysteine HCl H2O Monohydrate 7048-48-6
L-cysteine HCl H2O anhydrous 5289/1/1
L-cystine 56-89-3
L-glutamic acid 56-86-0
L-glutamic acid Hydrochloride 38-15-8
L-glutamine 56-85-9
glycine 56-40-6
L-histidine 71-00-1
L-histidine HCl H2O 5934-29-2
L-histidine HCl H2O 5934-29-2
L-methionine 63-68-3
L-Phenylalanine 63-91-2
L-Proline 147-85-3
L-serine 56-45-1
L-threonine 72-19-6
L-tryptophan 73-22-3
L-tyrosine 60-18-4
L-Valine 72-18-4


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