6. AOACSPIFANMethods-2018Awards

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Mottier: J ournal of AOAC I nternational V ol. 98, N o . 4, 2015  1133

70–120% range. Exception was recovery for a milk-based formula at the 1 µg/kg fortification level (134%). A small peak was observed at the transition reaction used for quantification in the related unfortified sample extract, meaning that sodium fluoroacetate might be present at a concentration well below the quantification capability of this method. This may explain this Table 2015.03F. Samples considered for the validation (SPIFAN kit) Infant formulae Batch Manufacturer (USA) Milk-based K16NTAV PBM Nutritionals Soy-based E10NWZC PBM Nutritionals Partially hydrolyzed milk-based 410057652Z Nestlé Partially hydrolyzed soy-based 410457651Z Nestlé High-fat nutritional 00729RF00 Abbott Nutrition High-protein nutritional 00730RF00 Abbott Nutrition QC samples (certified, P -test, in-house reference samples, or spiked samples) must be regularly included and analyzed in duplicate. Spiked experiment .—Spike the test portion with 20 µL (for powdered matrices) or 100 µL (for liquid matrices) of standard working solution 0.05 µg/mL, C ( d ), at the same time as the IS is added, E ( a ). This corresponds to 10 µg/kg spiking level. Calculate the recovery rate (Rec) of the spiked sample using the following equation: 100 Re × − = Spiked N T c ρ ρ ρ where ρ T is the total concentration of sodium fluoroacetate measured in the spiked sample in micrograms per kg. ρ N is the native concentration of sodium fluoroacetate measured higher recovery value. J. Internal Control Plan

Table 2015.03D. Typical MS parameters for the analysis of sodium fluoroacetate Parameter Applied Biosystems Sciex 5500 Ionization type Electrospray (ESI) Polarity Negative ionization Spray voltage –4500 V Source block temperature 500°C Gas Curtain gas: 30 psi

Ion source gas 1 (GS1): 40 psi Ion source gas 2 (GS2): 40 psi Vertical micrometer value: 5.0 Horizontal micrometer value: 5.0 Electrode protusion: 1.0 mm

Source position adjustments

–15

Collision energy (CE)

–10 V

Entrance potential (EP)

Collision exit potential (CXP) Declustering potential (DP)

–9 V

–45 V

Medium (6)

CAD gas pressure (MRM)

High on each quadrupole

Resolution

Scan time (for each transition)

100 ms

( a )  Linearity .—Linearity was verified over the 0–2 area ratio range, corresponding to 0–0.8 ng sodium fluoroacetate (0.4 ng IS) injected on-column. The calibration follows a linear model with R 2 > 0.99 and relative standard deviation of the average of response factors <15%. ( b )  LOQ .—LOQ is 1 µg/kg for infant formulae. This concentration corresponds to the lowest fortification level considered during validation. ( c )  Recovery, repeatability, and intermediate reproducibility precisions .—Precision data are described in Table 2015.03G .All performance data fulfilled SANCO/12571/2013 requirements, i.e., both CV(r) and CV(iR) ≤ 20% and recoveries within the

Table 2015.03E .  Transition reactions monitored for the analysis of sodium fluoroacetate (as its fluoroacetate anion) and its corresponding IS and peak area ratios along with their limit of acceptance according to CD 2002/657/EC (1) Transition reactions ( m/z ) used for Peak area ratio ± limit, % Quantification Analyte confirmation Fluoroacetate 77.0 → 33.0 a 77.0 → 57.0 a 0.80 ± 20 13 C 2 -Fluoroacetate (IS) 79.0 → 34.0 79.0 → 59.0 0.68 ± 20 a  m/z 57 corresponds to the loss of hydrofluoric acid [M-HF] - and m/z 33 to the loss of carbone dioxide [M-CO 2 ] - .

Table 2015.03G. Performance characteristics

Recovery, % a

CV(r), %

CV(iR), %

Sample

1 µg/kg

10 µg/kg

1 µg/kg

10 µg/kg

1 µg/kg 10 µg/kg

Milk-based formula Soy-based formula

134 117 111 116 112

105 103 108 103 101

6 6 4 9 4 4

3 2 5 2 3 2

11

4 3 4 2 4 2

8

Partially Hydrolyzed milk-based formula Partially hydrolyzed soy-based formula

9 8 7 6

High-fat nutritional formula High-protein nutritional formula

96

99

a  Recovery data for sodium fluoroacetate were calculated from values obtained under intermediate reproducibility conditions.