高速液体クロマトグラフ法による食品中の8種の保存料及びサッカリンナトリウムの一斉分析法

抄録

A method for the simultaneous analysis of eight kinds of preservatives and sodium saccharin (SacNa) in food products using ion-pair high performance liquid chromatography (HPLC) was developed. The preservatives of interest were dehydroacetic acid (DHA), sorbic acid (SoA), benzoic acid (BA), ethyl p-hydroxybenzoate (Et-PHBA), propyl p-hydroxybenzoate (n-Pro-PHBA), isopropyl p-hydroxybenzoate (iso-Pr-PHBA), butyl p-hydroxybenzoate (n-Bu-PHBA) and isobutyl p-hydroxybenzoate (iso-Bu-PHBA). These food additives were separated on an inertsil ODS-2 column (150 x 4.6 mm I.D.) using 50 mM monosodium dihydrogenphosphate-acetonitrile solution (66:34) containing 2 mM cetyltrimethylammonium bromide as the mobile phase and detected with a photodiode array detector at 305 nm for DHA, 254 nm for SoA, Et-PHBA, n-Pr PHBA, iso-Pr-PHBA, n-Bu-PHBA and iso-Bu-PHBA, and 230 nm for BA and SacNa. Comparison of the measured spectra with reference spectra allowed qualitative analysis (Fig. 1 and 2). The combination of dialysis extraction and liquid extraction with organic solvent is often used for pretreatment. However, purification with large amounts of organic solvents after dialysis extraction is a serious concern in terms of inductrial hygiene. In addition, the use of many types of analytical instruments causes operational complexity. For these reasons, a new method for concentrating and purifying dialysis extracts was developed. A comparison of four types of mini-columns revealed the Sep-Pak PS-2 column to have the best retainability (Fig. 3). Ten ml of methanol was used as the eluent from this column (Fig. 4). When 3, 0.5 and 0.01 g/kg of standard substances were added to the samples, excellent average recoveries of 99.1% were achieved (Table 1). The results obtained from 21 samples, preservatives or SacNa being detected were in excellent agreement with the values of dialysis-gas chromatography (Table 2 and Fig. 5). Thus, combination of dialysis extraction and solid phase extraction facilitates handling of many samples of various types, reducing the work load and the amounts of organic solvents required.