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