AOAC SPIFAN Nutrients ERP-Final Review (Jan. 2019)

D raher & W hite : J ournal of AOAC I nternational V ol . 101, N o . 4, 2018  1245

Table 2017.03A. Tryptophan SLV data: Precision Sample type

SPIFAN code a No. of replicates b Mean, g/100 g RTF c

RSD r

RSD iR

SRM 1849a

CLC10-B

12 12 12 12 12 12 12 12 12 12 12 12 12 12

20.1 25.3 18.3 25.7 24.1 21.4 23.7 32.2 23.2 19.5 18.3 22.4 70.6 91.3

0.37 1.51 0.56 0.97 4.95 6.92 0.82 2.02

Infant formula powder, partially hydrolyzed milk-based 410057652Z Infant formula powder, partially hydrolyzed soy-based 410457651Z

Toddler formula powder, milk-based Infant formula powder, milk-based Adult nutritional powder, low-fat

4052755861 4044755861 00859RF00 00866RF00

0.2 0.9

1.82

1.7

Child formula powder Infant elemental powder

0.94 1.33 0.24 1.56

00795RF

Infant formula powder, FOS/GOS-based Infant formula powder, milk-based Infant formula powder, soy-based Infant formula, RTF milk-based Adult nutritional, RTF high-protein Adult nutritional, RTF high-fat

50350017W1

2

2.42

K16NTAV E10NWZC

0.31 1.69

0.2

2.27

EV4H2R

0.45 1.79 1.86 3.68

00730RF00 00729RF00

0.3

1.91

a  Materials from the SPIFAN Sample Kit. b  Duplicates on each of 6 days performed by one laboratory. c  RTF = Ready-to-feed.

( g ) Volumetric pipets .—Glass, class A, assorted sizes. C. Reagents ( a ) Methanol .—HPLC grade (Fisher; Part No. A456). ( b ) Sodium phosphate monobasic .—HPLC grade (Macron; Part No. 7892-04). ( c ) Phosphoric acid, 85% .—Mallinckrodt; Part No. 3563-46. ( d ) Trizma base, ≥99.9% .—Sigma; Part No. T1503. ( e ) Hydrochloric acid (HCl), 6 N .—GFS Chemical; Part No. 504. ( f ) Laboratory water .—ASTM type 1. ( g ) L-Tryptophan reference standard (C 11 H 12 N 2 O 2 ) .—USP; Cat. No. 1700501. ( h ) 5-Methyl-DL-tryptophan (C 12 H 14 N 2 O 2 ) .—Sigma; Cat. No. M-0534.

preparations and the analytes of interest detected and quantified fluorometrically. B. Apparatus and Materials ( a ) HPLC system .—Equipped with an autosampler, column oven to maintain 30°C, fluorescence detector, binary or quaternary HPLC pump with degasser, and HPLC peak area integrator or chromatography data processor. ( b ) Analytical column .—YMC PACK C8; 3 μm particle, 3 × 50 mm (YMC America, Inc.; Product No. OC12S03-0503WT). ( c ) Analytical balance .—Readable to 0.001 mg. ( d ) Oven .—Constant-temperature oven capable of maintaining 50 ± 1°C. ( e ) Syringe filter .—ACRODISC disposable filter assembly, 0.45 μm pore size (Gelman Scientific; Cat. No. 4217). ( f ) Volumetric flasks .—Glass, class A, assorted sizes.

Table 2017.03B. Tryptophan SLV data: Accuracy

50% Overspike

100% Overspike

SPIFAN code CLC10-B

No. of replicates a

Spiking material

Native Trp level, g/100 g Avg. rec., % RSD, % Avg. rec, % RSD, %

Sample type SRM 1849a

12

BSA 20.06 BSA 25.28

99.9

1.83

100.9

2.4

Infant formula powder, partially  hydrolyzed milk-based Infant formula powder, partially  hydrolyzed soy-based Adult nutritional powder, low-fat

410057652Z 12

104.3

3.3

104.1 2.71

410457651Z 11

BSA 18.33

103.7

8.6

101.5

4.8

00859RF00

12 10 12

BSA 21.39 BSA 32.22 BSA 19.51 BSA 18.27

96.2

5.2 2.5

99.5

3.9 2.7

Infant elemental powder

00795RF

100.7 100.5

102.4

Infant formula powder, milk-based K16NTAV

2.99 5.09

101.7 1.99

Infant formula powder, soy-based E10NWZC 12

93.8

99.5

3.53

Adult nutritional, RTF high-fat 1.3 a  Samples spiked in duplicate with two levels of spikes over 3 days. Samples with <12 replicates contained data points that were confirmed outliers. 00729RF00 12 BSA 91.3 104.8 1.6 104.9