A rapid method for the trace level detection of ametryn and atrazine residues in food matrices was developed by using a selective ambient mass spectrometry (AMS) ion source based on molecularly imprinted polymer modified iron sheet (MIPIS) in combination with electrospray ionization mass spectrometry (ESI-MS). Molecularly imprinted polymer (MIP) using cyanazine as template molecule was prepared by polymerization of methacrylic acid (MAA) and aniline in aqueous solution. MIPIS was used as an extraction tip for rapid enrichment of ametryn and atrazine in soy milk powder, wheat and milk before direct analysis by AMS ion source coupled to ESI-MS. The results showed that the linearity of this method ranged from 0.2 to 200 μg/L, with correlation coefficients of 0.9982 and 0.9997 for ametryn and atrazine, respectively. The average recoveries of ametryn and atrazine at three spiked levels ranged from 81.05% to 109.66%. The limits of detection (LODs) and the limits of quantification (LOQs) of the analytes were 0.2–0.5 μg/kg and 0.6–1.5 μg/kg, respectively. This study has provided a simple and sensitive method that can effectively avoid the tedious sample pretreatment and timeconsuming chromatographic separation for rapid detection of trace levels of triazine pesticide residues in foods.

Technology trends in sample pretreatment, a crucial step in the analysis of complex samples, are of great significance to the development of analytical chemistry. Magnetic solid phase extraction (MSPE) is a novel sample pretreatment technique using magnetic or magnetizable materials as adsorbents. Thanks to its advantages including easy operation, short extraction time, strong anti-interference ability and good biocompatibility, MSPE represents one of the most promising approaches in the field of sample pretreatment. In recent years, with the rapid development of various adsorbent preparation techniques, novel magnetic nanomaterials-based MSPE is widely used for the isolation and enrichment of a variety of compounds in foods. In this review, we summarize the up-to-date advances in the application of MSPE based on graphene/graphene oxide (G/GO), carbon nanotube (CNT), metal organic framework materials (MOFs), covalent organic framework materials (COFs), molecularly imprinted polymers (MIPs), nanocomposite materials or functional polymer materials in food safety detection, and we discuss future development prospects in this field.

A magnetic solid phase extraction (M-SPE) based on covalent organic framework materials coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method was developed for the efficient determination of four aflatoxins (AFs) in tea. The samples were extracted with a mixture of acetonitrile, water and glacial acetic acid (8.0:1.9:0.1, V/V) and centrifuged. The supernatant was evaporated to almost dryness, re-dissolved in water and pH adjusted, extracted M-SPE and filtered, and the filtrate was detected in the positive ion mode. The calibration curves for all analytes were linear in the range of 0.05–50 μg/L with coefficients of determination (R²) > 0.999 2, the spiked recoveries were in the range of 67.6%-103.7%, and the relative standard deviations (RSDs) for intra- and inter-day precisions were less than 9.24%, the limits of detection (LODs) were in the range of 0.01-0.06 μg/kg, and the limits of quantification (LOQs) of the developed method were in the range of 0.05-0.20 μg/kg. The covalent organic framework material prepared in this study has a strong adsorption capacity for AFs, and M-SPE-HPLC-MS/MS is suitable for the rapid, highly sensitive and accurate detection of AFs in tea.

A rapid method for the determination 107 illegally added nafils in compressed candies, honey and beverage was developed by ultra-high performance liquid chromatography coupled with quadrupole orbitrap high-resolution mass spectrometry. The samples were extracted with methanol and separated on a Waters Acquity UPLC BEH C₁₈ column (2.1 mm × 100 mm, 1.7 μm) with gradient elution using a mobile phase consisting of acetonitrile and 0.1% formic acid in water. The detection was conducted in both positive and negative ion modes, and a full MS scan/data dependent MS² mode was used to collect data. The 107 nafils showed good linearity in the concentration range of 4–300 μg/L, with correlation coefficients (R²) greater than 0.99. The limits of detection (LODs) were 0.1–1 mg/kg, and the limits of quantification (LOQs) were 0.2–2 mg/kg. The average recoveries ranged from 82.5% to 117.0% at three spiked levels of 2, 5, 10 mg/kg, with relative standard deviations of 0.9%–10.0% (n = 6). This method was fast, accurate, sensitive, and suitable for the rapid identification and quantification of illegal additives in foods.

Meat products, being rich in nutrients, often provide an ideal environment for microbial growth. Even under low temperature storage, most microorganisms remain active and retain partial virulence. Therefore, screening for pathogenic bacteria in meat products is crucial. This study developed a triple-fluorescence ERA (enzymemediated recombinase polymerase amplification) rapid detection method based on enzyme recombinase amplification (ERA) technology. Performance analyses were conducted on the method’s specificity, sensitivity, and detection limits. Additionally, the applicability of the method was validated using commercially available refrigerated meats and compared to the industry standard SN/T 1870―2016 real-time fluorescent polymerase chain reaction (PCR)method. The results show that a triple-fluorescent ERA rapid detection method was successfully constructed for three key pathogens: Staphylococcus aureus, Salmonella and Listeria monocytogenes. After optimization, the method could simultaneously detect the three pathogens within 12 min from a single reaction. The minimum detection limit is 10^-3 ng/µL. In artificially contaminated samples, after 6 hours of pre-enrichment, the method can simultaneously detect contamination levels of 1 CFU/mL for all three pathogens. The sampling results of commercially available refrigerated meat show that the detection rates for Staphylococcus aureus, Salmonella, and Listeria monocytogenes were 19.35%, 12.90%, and 6.45%, respectively, which align with the detection results of the industry standard SN/T 1870―2016. These fully demonstrate the accuracy and applicability of the method. This study not only helps reduce the risk of disease caused by foodborne pathogens but also provides solid technical support for future rapid detection of foodborne pathogens.

An analytical method based on ultra-high performance liquid chromatography-tandem mass spectrometry was developed for the simultaneous detection of nine commonly used quaternary ammonium compounds (QACs) in various food matrices including vegetables, fruits, and aquatic products. The enrichment and purification of QACs were achieved using an improved quick, easy, cheap, effective, rugged and safe (QuEChERS) method, and the separation was performed on a BEH C₁₈ column (100 mm × 3.0 mm, 1.7 μm) with gradient elution. QACs were detected using an electrospray ionization source in the positive ion mode. The limits of detection and quantification for the nine QACs in vegetables, fruits, and aquatic products were 0.2–5.0 and 1.0–10.0 μg/kg, respectively, and good linearity was observed for all analytes within their respective concentration ranges (R² > 0.99). The recoveries for spiked samples were in the range of 65.24%–118.63% with relative standard deviations (RSDs) of 0.19%–6.77%. When the developed method was applied to commercial foods and dietary samples in Beijing, detection rates of 30.43% and 12% were obtained, respectively. The dietary risk of QAC residues was acceptable.