Abstract
We established and validated a sensitive multi-residue analytical method for identifying benzophenone (BP) and nine BP derivatives (2,4-dihydroxybenzophenone [BP-1], 2,2′,4,4′-tetrahydroxydroxybenzophenone, 2-hydroxy-4-methoxy benzophenone, 2,2′-dihydroxy 4-methoxy benzophenone, 2-hydroxybenzophenone [2-OHBP], 4-hydroxybenzophenone, 4-methylbenzophenone [4-MBP], methyl-2-benzoylbenzoate, and 4-benzoylbiphenyl). Solid−liquid extraction pretreatment and ultra-high-performance liquid chromatography−tandem mass spectrometry (UHPLC−MS/MS) were employed in an analysis of 85 packaged cereal-based food samples (25 pastry, 50 rice, and 10 noodle samples). The method had satisfactory linearity (R2 ≥ 0.995), low limits of detection (pastry: 0.02−4.2 ng/g; rice and noodle: 0.02−2 ng/g), and favorable precision, with within-run and between-run coefficient of variation ranges of 1−29% and 1−28%, respectively. BP and 4-MBP were detected in 100% of the pastry samples, and BP-1 and 2-OHBP were found in 76% and 56% of the pastry samples, respectively. BP and 2-OHBP were found in 92% and 38% of the rice samples, respectively. BP was found in 50% of the noodle samples. BP contributed the most to the total level of BPs in pastries, with significantly higher mean ± standard deviation (range) levels for pastries (26.8 ± 32.6 [1.8−115.4] ng/g) than rice (1.2 ± 2.0 [0.4−13.4] ng/g) and noodles (0.7 ± 0.7 [0.4−1.9] ng/g); p < 0.0001). The trace levels of 4-MBP identified in the samples demonstrate the need for the development of analytical methods with high sensitivity and specificity; the proposed method satisfies this need.