A high-throughput supramolecular solvent method for benzophenone quantification in juice packs via liquid chromatography-mass spectrometry

Abstract

Benzophenones (BPs) are among the most frequently detected photoinitiators in liquid packaged food, mainly using liquid chromatography tandem mass spectrometry (LC-MS/MS). However, sample treatments in these methods are demanding in terms of resources and expenses, are little or not sustainable, and prevent high throughput sample processing. In this paper, supramolecular solvents with properties of restricted access materials (SUPRAS-RAM) were firstly used to make simpler, faster and more sustainable the sample treatment in the determination of BPs in juices. The SUPRAS-RAM formed instantaneously in the juice by the addition of hexanol (75 µL) and tetrahydrofuran (600 µL). The BPs were extracted after vortexing the mixture for 2 min. Macromolecules in the sample, including carbohydrates, fibers and proteins were not extracted in the SUPRAS-RAM by physical or chemical mechanisms, so the extract could be directly injected into the LC-MS/MS system. Detection limits were in the range of 0.013-0.414 ng mL-1. Average recoveries of BPs in juices (orange, tomato, pineapple, apple) at three concentration levels (1, 5 and 20 ng mL-1) were 70.4-118%, with relative standard deviations in the interval 0.05-9%. Matrix effects were all in the range of ±20%. Unlikely most of the reported methods for BPs based on LC-MS/MS, external calibration gave reliable quantification. Three BPs were detected and/or quantified in the ten juice samples analysed; namely benzophenone, 2-hydroxy-4-methoxybenzophenone and 4-methylbenzophenone. The characteristics of the sample treatment here proposed (i.e. low solvent consumption, integration of BP extraction and sample clean-up and a simple and fast procedure, and the effective removal of interferences) render this method competitive for BPs quantification with respect to previously reported methods.