Dispersive liquid–liquid microextraction and gas chromatography–mass spectrometry determination of polychlorinated biphenyls and polybrominated diphenyl ethers in milk

Abstract

An effective multi-residue pretreatment technique, solid-phase extraction (SPE) combined with dispersive liquid-liquid microextraction (DLLME), was proposed for the trace analysis of 14 polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in milk samples using gas chromatography-mass spectrometry (GC-MS). Interesting analytes in milk samples were extracted with hexane after protein precipitation. The hexane extracts were loaded on an LC-Florisil column to isolate analytes from the milk matrix. The elutes were dried and dissolved in acetone, which was used as the disperser solvent in subsequent DLLME procedures. The effects of several important parameters on the extraction efficiency were evaluated. Under the optimized conditions, a linear relationship was obtained in the range of 0.02-10.00 μg/L (PCBs) and 0.5-100.00 μg/L (PBDEs). The LOD (S/N=3) and relative standard deviations (RSDs, n=5) for all analytes were 0.01-0.4 μg/L and 0.6-8.5%, respectively. The recoveries of the standards added to raw bovine milk samples were 74.0-131.8%, and the repeatabilities of the analysis results were 1.12-17.41%. This method has been successfully applied to estimating PCBs and PBDEs in milk samples.

Separation and Preconcentration by Dispersive Liquid–Liquid Microextraction Procedure: Recent Applications

“…The performance of DLLME combined with GC-MS has been illustrated with the determination of several analytes: drugs [37], fungicides [38], endocrine disruptors [39][40][41]57], chlorophenols and haloanisoles [42,55], pesticides [43,45,50,59], preservatives [46], additives [47], polycyclic aromatic hydrocarbons [48,49], UV filters [51,52], flame retardants [58,60,61], N-nitrosamines [62], etc.…”

“…Acetonitrile solution obtained by DSPE cleanup was directly used as the dispersant for the subsequent DLLME, which made the combination of the DSPE with the DLLME much more straightforward. Liu et al [61] use SPE combined with DLLME. In this work, interesting analytes in milk samples were extracted with hexane after protein precipitation.…”

Determination of Aroclor 1260 in soil samples by gas chromatography with mass spectrometry and solid-phase microextraction

“…Methods using SPME have been reported for the determination of PCBs in different matrices such as water [16], soil [21], ash [22], and tissues [15]. All of these applications focused on the quantitative analysis of selected PCB congeners rather than directly modeling the Aroclors.…”

Determination of polychlorinated biphenyls in seawater using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry with the aid of experimental design

“…7 This has promoted rapid developments in sample preparation and chromatographic techniques in the analysis of PCBs. 8,9 Extraction and preconcentration techniques, such as liquid-liquid extraction (LLE), solid-phase extraction (SPE) and solid-phase microextraction (SPME), have been widely used to determine PCBs. 1,10,11 LLE and SPE are mainly used, but they have some fundamental limitations.…”