AOAC SPIFAN Nutrients ERP (December 7, 2022)

Amino-07 (SLV) 10-2022 FOR ERP USE ONLY DO NOT DISTRIBUTE

Table 5: Intermediate precision of taurine LC-MS method

Confidence Interval b (%)

RSD r

a

Sample

(%)

NIST 1869 reference material powder

7.3 4.9 3.4 5.0 5.2 3.7 4.0

5.5–10.4 3.7–7.0 2.5–4.8 3.7–7.1 3.9–7.3 2.7–5.2 3.0–5.7

partially hydrolysed milk-based infant formula powder

bovine milk-based infant formula powder

soy-based infant formula powder FOS/GOS infant formula powder

child elemental powder

NIST 1849a reference material powder

a Repeatability relative standard deviation b 95% confidence interval of repeatability relative standard deviation

SMPR concentrations Repeatability at the concentration ranges specified in SMPR 2014.013 were evaluated by spiking an adult nutritional formula at three concentration levels in the ranges: low (~2 mg hg − 1 RTF), medium (~20 mg hg − 1 RTF), and high (~200 mg hg − 1 RTF). Spiked samples, unspiked samples, and spiked standards were analysed by the method as independent replicates eight times. Repeatability as % RSD r and 95 % confidence interval were calculated and compared to the precision requirements of the SMPR (Table 6; Appendix D) [5].

Table 6: Repeatability of taurine in spiked samples compared to SMPR

Confidence Interval b (%)

RSD r

SMPR limit (%)

a

Spiked adult nutritional formula

(%)

low concentration (~2 mg hg − 1 RTF) medium concentration (~20 mg hg − 1 RTF) high concentration (~200 mg hg − 1 RTF)

4.5 1.8 1.8

2.8–9.3 1.6–5.5 1.1–3.7

≤ 7 ≤ 5 ≤ 3

a Repeatability relative standard deviation b 95% confidence interval of repeatability relative standard deviation

The estimated values for repeatability at 2, 20, and 200 mg hg − 1 RTF level were 4.5, 1.8, and 1.8 % RSD r respectively, each of which complies with the limits specified in SMPR 2014.013.

Limit of Quantitation The limit of detection (LoD) is the lowest concentration of the analyte that can be detected by the method at a specified level of confidence. The limit of quantitation (LoQ) is the minimum

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