Validation, measurement uncertainty, and determination of polysorbate-labeled foods distributed in Korea

This study reports the improvement and validation of a colorimetric method to quantify polysorbates (20, 60, 65, and 80) in food by measuring absorbance at 620 nm using ultraviolet–visible spectrophotometry. The method was validated for linearity, limit of detection (LOD), limit of quantitation (LOQ), precision, accuracy, and measurement uncertainty. The coefficient of determination was linear (r² ≥ 0.9991) over the measured concentration range of 50–1000 mg/L. The LOD and LOQ were 2.3–4.9 and 7.0–15.0 mg/kg, respectively. Intra-day and inter-day accuracy and precision were 91.9–104.1% and 0.1–1.1% RSD, and 91.6–103.8% and 0.4–5.0% RSD, respectively. The result of inter-laboratory recovery was 90.9–99.8% and the measurement uncertainty was < 16% with the compliance of the CODEX recommendation. Sauce, bread, whipped cream, rice cake, ice cream, and various other polysorbate-labeled food products (n = 229, detection range; N.D.–16,442.3 mg/kg) distributed in Korea were analyzed to confirm the applicability of the analytical method.