AOAC 2019 First Action Methods
Table 2019.09A. AA stock standard preparation No. Amino acids (AA)
Weight (mg) a
MW correction for salt forms
1 2 3 4 5 6 7 8 9
Alanine
110 240 300 200 150 500 150 260 150 150 300 375 200 200 290 200 200 200 65
Arginine-HCl Aspartic acid
Arginine = arginine-HCl x 174.2 / 210.7
Citrulline Cystine
Glutamic acid
Glycine
Histidine–HCl.H 2 O Hydroxyproline
Histidine = histidine-HCl.H 2 O x 155.2 / 209.6
10 11 12 13 14 15 16 17 18 19 20
Isoleucine
Leucine
Lysine-HCl Methionine Phenylalanine
Lysine = Lysine-HCl x 146.2 / 182.7
Proline Serine Taurine
Threonine Tyrosine
Valine 300 a Guideline only, record and use the actual weight for the calculation of AA concentrations.
Notes : Calculate the concentration of each amino acid using the relevant purity factor. Purity factor can be calculated from nitrogen determination.
Concentration (mg/100 mL) = W (mg) x purity factor Purity Factor = Observed nitrogen content / theoretical nitrogen content
Table 2019.09B. AA calibration standards Cal stds AA intermediate std (µL)
6 M NaOH (µL)
Internal Std 2.5 mM (µL)
Total volume (mL)
Blank Std 1 Std 2 Std 3 Std 4 Std 5
0
0
400 400 400 400 400 400
10 10 10 10 10 10
100 200 400
100 200 400
1000 2000
1000 2000
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