Abstract:

A new method for sample pretreatment using improved QuEChERs was established, and 289 organic pollutants with health risks could be identified and quantified through gas chromatography-orbitrap high-resolution mass spectrometry (GC-Orbitrap HRMS). A high-resolution database of 289 environmental pollutants belonging to ten categories, including organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), phthalates (PAEs), polychlorinated biphenyls (PCBs), and other agricultural chemicals (ACs), was established for the non-targeted screening and quantitative analysis. A simple method for biological sample preparation using improved QuEChERs was proposed by combining a conventional QuEChERs method and a column purification method. After purification using a Florisil column, the lipid content was reduced by 99.9%, which significantly reduced the interference of the matrix effect observed during the analysis. Furthermore, simultaneous high-accuracy qualitative screening and quantitative analysis of the target compounds were performed through high-resolution mass spectrometry (60000 resolution) conducted in the full scan mode. The limits of quantification were 0.56-57.8 pg/g, presenting a large linear range (~10⁶), and the recovery range was 40%-120%. Due to the high-resolution and sensitivity of Q Exactive GC-Orbitrap HRMS, the limits of quantification of the target compounds were significantly lower than those achieved through methods based on conventional chromatography and mass spectrometry. Moreover, ultratrace organic contaminants that cannot be detected by conventional methods can be accurately quantified by the proposed method. Sea cucumber samples collected at the breeding site were analyzed using the proposed high-coverage multi-objective analytical method, and more than 100 types of organic pollutants were detected; the mean contents of PAHs, ACs, PAEs, and OCPs were 157.8, 153.2, 64.4, and 46.4 ng/g dw, respectively, which were higher than those of other pollutants. Some new contaminants, such as 9-chlorofluorene, 5-chloroacenaphthene, and 3-methylcholanthrene, were detected at very low contents for the first time in the sea cucumber samples. The proposed method is simple and efficient, allows the detection of pollutants at very low contents, and provides accurate and reliable results. Thus, this high-coverage multi-objective analytical method can be widely used for broad-spectrum screening and accurate quantification of contaminants in various aquatic products, providing technical support for food safety control.

Key words: gas chromatography-orbitrap high-resolution mass spectrometry (GC-Orbitrap HRMS), QuEChERs, nontarget analysis, environmental pollutants, sea cucumber