AOAC SPIFAN Nutrients ERP (December 7, 2022)

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

The range of taurine concentrations in linearity standards was 0.06–600 μ g mL − 1 , which is equivalent to a sample powder concentration of 0.27–2700 mg hg − 1 RTF which extends beyond both the lower and upper limits of the range specified in the SMPR 2014.013.

Precision

Typical sample concentrations Repeatability is defined as the precision of a series of results of a test material with the same measurement system and analyst over a short period of time. Intermediate precision is a measure of precision as a series of results of a test material under similar laboratory conditions over an extended period of time. Precision as repeatability and intermediate precision was assessed by testing duplicate pairs of samples ( n = 12) of different products on six separate days. Repeatability as % RSD r , intermediate precision as % RSD iR , and 95 % confidence intervals were calculated and compared to results expected based on the Horwitz ratio (Tables 4, 5; Eqns 6–12; Appendix D) [5, 6].

Table 4: Repeatability of taurine in powder samples by LC-MS method

Confidence Interval b (%)

RSD r

a

Sample

HorRat r

(%)

NIST 1869 reference material powder

6.4 4.6 2.8 4.5 3.9 3.5 1.6

4.8–9.1 3.5–6.6 2.1–4.0 3.4–6.4 3.0–5.6 2.6–4.9 1.2–2.3

0.6 0.4 0.2 0.4 0.4 0.3 0.1

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

The estimated repeatability for the candidate method ranged between 1.6–6.4 % RSD r and HorRat r values were within or better than the expected range of 0.3–1.3.

Intermediate precision values ranged from 3.4–7.3 % showing that method likely would provide acceptable precision in multi-laboratory study. Intermediate precision is not a requirement of SMPR 2014.13.