Department of HPLC and Element Analysis, Intertek Food Services GmbH, Bremen, Germany.
Department of Large Scale Food Fortification, The Global Alliance for Improved Nutrition, Geneva, Switzerland.
Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2022 Jan;39(1):24-34. doi: 10.1080/19440049.2021.1977854. Epub 2021 Sep 29.
Large-scale food fortification of vegetable oils with vitamin A has been implemented successfully for decades in numerous African and Asian countries, contributing demonstrably to reductions in vitamin A deficiency. For these programmes, reliable and validated analytical data are essential to demonstrate compliance with legal standards and fortification levels. Commonly, many analytical laboratories use a saponification method for the quantitative analysis of retinyl palmitate (the mostly used form of vitamin A for fortification) in fortified oils, which implies a multiple-step procedure with long analysis times and the potential risk of analyte loss. The aim of the present study was to develop and validate a direct High-performance Liquid Chromatography (HPLC) method that reduces these sample preparation steps, leading to the cost- and time-efficient quantification of retinyl palmitate in fortified oils. Oil samples are dissolved into the HPLC solvents, then injected directly into a common C column, and subsequently detected by a fluorescence detector. The limit of quantification (1.0 mg retinyl palmitate kg) and the working range of 1.0-100 mg retinyl palmitate kg with a linearity of R = 0.9989 are appropriate to analyse fortified oil samples. The method also showed adequate precision (RSD between 1.1% and 3.1%) and recoveries (86-103%) at two different concentration levels. The accuracy of the direct HPLC method was additionally proven by the comparison of spiked samples with two external laboratories that used the saponification method. The robustness of the method was confirmed by the analysis of various spiked edible oils. The HPLC column is not deteriorated by the lipid matrix and shows excellent stability and long lifetime. Also, 9--retinyl palmitate formed mainly by light exposure could be detected by this method. The direct HPLC method is a well-suited alternative to the saponification method for the rapid and reliable routine analysis of fortified oil samples.
几十年来，在许多非洲和亚洲国家，已成功大规模地将维生素 A 添加到植物油中进行强化，这显然有助于减少维生素 A 缺乏症。对于这些项目，可靠和经过验证的分析数据对于证明符合法律标准和强化水平至关重要。通常，许多分析实验室使用皂化法对强化油中的视黄醇棕榈酸酯（强化中最常用的维生素 A 形式）进行定量分析，这意味着需要经过多个步骤，分析时间长，并且分析物有损失的风险。本研究旨在开发和验证一种直接高效液相色谱（HPLC）方法，该方法可减少这些样品制备步骤，从而实现强化油中视黄醇棕榈酸酯的成本效益高且耗时短的定量分析。将油样溶解于 HPLC 溶剂中，然后直接注入普通 C 柱，然后用荧光检测器进行检测。定量限（1.0 mg 视黄醇棕榈酸酯 kg）和工作范围为 1.0-100 mg 视黄醇棕榈酸酯 kg，线性度 R=0.9989，适用于分析强化油样。该方法还显示出适当的精密度（1.1%至 3.1%之间的 RSD）和回收率（86-103%），在两个不同浓度水平下。通过与使用皂化法的两个外部实验室比较添加样品，进一步证明了直接 HPLC 方法的准确性。通过分析各种添加的食用油脂，确认了该方法的稳健性。HPLC 柱不会因脂质基质而恶化，并且显示出出色的稳定性和长寿命。此外，还可以通过该方法检测主要由光照形成的 9--视黄醇棕榈酸酯。该直接 HPLC 方法是替代皂化法进行强化油样品快速可靠常规分析的理想方法。
