Objective To establish a magnetic solid phase extraction (MSPE) approach based on covalent organic framework materials in combination with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the efficient determination of 9 kinds of carbamate pesticides (CPs) in Vigna unguiculata. Methods After the extraction of Vigna unguiculata samples, the novel Fe₃O₄@TAPOB-BDTB material was employed for magnetic solid-phase extraction and purification. After filtration, the samples were separated by a C₁₈ chromatographic column and quantitatively analyzed using multiple reaction monitoring in the electrospray positive ion mode. Results The established analytical methods for the 9 kinds of CPs exhibited excellent linearity within the concentration range of 0.02-100.00 μg/kg, with the determination coefficients (r²) all exceeding 0.9989. The spiked recovery rates were within the range of 80.33%-108.63%, and both the intra-day and inter-day precisions were less than 8.89%. The detection limits of the methods were 0.005-0.010 μg/kg, and the limits of quantitation were 0.02 μg/kg, which were significantly below the maximum residue limits specified in GB 2763—2021 National food safety standard-Maximum residue limits of pesticides in food and EU Regulation No 396/2005, ensuring compliance within an academic context. Conclusion The covalent organic framework materials synthesize in this study demonstrate exceptional adsorption capacity for CPs via π-π interactions and hydrogen bonding. Furthermore, the develope MSPE-HPLC-MS/MS method enables rapid, highly sensitive, and precise detection of CPs in Vigna unguiculata, thereby offering an efficient and innovative approach for monitoring pesticide residues in agricultural products.

Objective To establish an analytical method for the determination of enrofloxacin residues in complex mixed matrix of the “soil-vegetable” system by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods The sample was subjected to vortex ultrasonic extraction with acidified acetonitrile extract [containing 5% ethylene diamine tetraacetic acid (EDTA)-Mcllvaine buffer solution], settling with centrifugation, getting solvent conversion and being filtered by 0.22 μm nylon filter membrane. The mobile phase was composed of acetonitrile and 0.1% formic acid aqueous solution (containing 2 mmol/L ammonium acetate), and the mixture was subjected to Waters ACQUITY UPLC ® BEH C₁₈ chromatographic column (2.1 mm×100 mm, 1.7 μm) gradient elution separation, using mass spectrometry as a detector for qualitative and quantitative analysis of enrofloxacin. Results In the mass concentration range of 1-200 ng/mL, the standard curve showed a good linear relationship (correlation coefficient=0.9996), the limit of detection of the method was 0.11 μg/kg, the recovery rates ranged from 87.4% to 103.3%, and the relative standard deviations (RSDs) were 0.4% to 4.0% (n=6). Conclusion This method has fast analysis speed, high accuracy and good repeatability, and is suitable for the detection of enrofloxacin residues in complex mixed matrix of the “soil-vegetable” system. It also has the potential to indirectly reveal the risk of antibiotic resistance genes (ARGs) contamination in the system.

Objective To evaluate the levels of metal elements contamination in Morella ruba Lour. from different production areas in Wenzhou and establish a comprehensive evaluation system. Methods The 121 Morella ruba Lour. samples and 68 soil samples from Morella ruba Lour. planting sites in Wenzhou were studied. The pH of the soil and 6 kinds of metal elements indicators, including chromium, nickel, arsenic, cadmium, mercury and lead, in both the soil and fruits were measured and analyzed. A fruit-soil correlation model (incorporating correlation analysis and principal component analysis of 13 parameters across 54 samples) was established. Results The qualification rate of Morella ruba Lour. samples was 94.21%, while the qualification rate of soil samples was only 39.71%; there was a varying degree of correlation between the metal elements content in Morella ruba Lour. fruits and soil, with a strong positive correlation between mercury in Morella ruba Lour. fruits and chromium and nickel in soil; principal component analysis identified chromium and cadmium in soil, as well as nickel, lead and arsenic in Morella ruba Lour., as the core indicators for evaluating the metal elements quality and safety of Morella ruba Lour.. Conclusion This study established a comprehensive evaluation system for metal elements quality safety in Morella ruba Lour., providing methodological references for regional agricultural product safety regulation.

Objective To evaluate the toxicological safety of xylooligosaccharides. Methods According to the national food safety standards, the safety of xylooligosaccharides was evaluated through acute oral toxicity test in mice, micronucleus tests in mammalian bone marrow red blood cells, chromosomal aberration tests in spermatocytes, Bacterial reverse mutation (Ames) test, and 28 day oral toxicity test. Results The acute maximum tolerated dose (MTD) of xylooligosaccharides in male and female mice was greater than 10000 mg/(kg·bw), which was classified as practically non-toxic; the micronucleus test of mammalian bone marrow red blood cells, chromosome aberration test of spermatocytes, and Ames test were all negative; set up 3 dose groups: 0 (basic feed control), 4167, 8333 and 16667 mg/(kg·bw) (equivalent to 25 times, 50 times and 100 times the maximum recommended intake), orally administered once a day for 28 consecutive days. The high-dose group of animals showed a decrease in total weight gain related to the test sample, changes in biochemical indicators such as alanine aminotransferase, alkaline phosphatase, glucose and urea nitrogen, and a decrease in organ weight and visceral to body ratio in male rats. However, there were no corresponding changes observed in the medium and low-dose groups (equivalent to 50 times and 25 times the maximum recommended intake) and the Weixing group. Conclusion Xylooligosaccharides do not show acute toxicity or genetic toxicity; the no observed adverse effect level (NOAEL) of the sample for 28 days of oral toxicity in female and male rats is 8333 mg/(kg·bw).

Objective To establish a method for rapid detection of toltrazuril and other veterinary drug residues in milk using ultra performance liquid chromatography-tandem mass spectrometry based on solid-phase extraction purification technology. Methods The samples were ultrasonically extracted with a 0.1% acetic acid-acetonitrile solution and purified using an solid phase extraction column (HMR-Lipid). Separation was achieved on a BEH C₁₈ chromatographic column with 0.1‱ acetic acid in water-acetonitrile as the mobile phase. The target compounds were ionized in the negative ion mode of electrospray ionization and detected in multiple reaction monitoring mode, with quantification performed using the internal standard method. Factors such as extraction, purification and chromatographic conditions of the target compounds in the samples were optimized. Results The target compounds had good linearity in the mass concentration range of 0.5-50.0 ng/mL, with correlation coefficients all greater than 0.999. The limits of detection were 0.23-0.52 μg/kg, and the limits of quantitation were 0.23-1.45 μg/kg. The spiked recoveries ranged from 92.4% to 105.2%, and the precisions were between 0.32% and 7.00%. Conclusion The sample pretreatment could be completed within 15 minutes. This method is simple, rapid, highly sensitive and accurate for both qualitative and quantitative analysis, and is suitable for the detection of toltrazuril and other veterinary drug residues in milk.

Objective To establish a method for the determination of the migration of 14 kinds of ultraviolet absorbers in aqueous food simulants and chemical alternative solvents (95% ethanol aqueous solution and isooctane) by high performance liquid chromatography. Methods The ultraviolet absorbers migrated into the aqueous food simulants were extracted twice with n-hexane by vortexing and shaking, and the combined extract was evaporated to dryness under reduced pressure and re-dissolved in tetrahydrofuran. The ultraviolet absorbers migrated into the chemical alternative solvents were evaporated to dryness and re-dissolved in tetrahydrofuran. A C₈ column was used for separation, with acetonitrile and water as the mobile phase and gradient elution. Detection was performed using a ultraviolet detector at a wavelength of 300 nm. Results The limits of detection of 14 kinds of ultraviolet absorbers were as low as 0.008 mg/L, and the limits of quantitation were 0.020 mg/L. The correlation coefficients of the 14 kinds of target compounds were above 0.999 within the linear range of 0.20-5.0 mg/L. The 3 levels of ultraviolet absorbers (0.02, 0.05 and 0.50 mg/L) were added to the food simulants or chemical alternative solvents, and 6 replicate experiments were conducted. The results showed that the recovery rates of each compound at each level were within the range of 82.4%-108.0%, and the relative standard deviations were less than 10%. Conclusion This method is accurate, efficient and simple, and can be used to simultaneously determine the migration amounts of 14 kinds of ultraviolet absorbers in aqueous simulants and chemical alternative solvents.

Objective To explore the optimal fermentation process of Vatica wine and analyze its flavor substances. Methods The fermentation conditions of Vatica wine were optimized by single factor experiments and Box-Behnken response surface analysis. The effects of yeast addition amount, fermentation temperature and fermentation time on the fermentation of green plum wine were analyzed. The flavor components of green plum wine were analyzed by headspace solid-phase microextraction and gas chromatography-mass spectrometry to determine the optimal process conditions. Single-factor experiments. Results The optimal technological conditions were as follows: Fermentation temperature 25 ℃, yeast addition 0.5 g/L, fermentation time for 8 days. Among them, 25 kinds of volatile flavor substances were detected. The main flavor active ingredients were alcohols, esters, aldehydes and ketones, terpenes, etc. They accounted for 59.28%, 9.07%, 17.00% and 0.96% of flavor substances, respectively. Conclusion The Vatica wine fermented by this condition is sweet and sour and has the unique fragrance of Vatica, which provides theoretical support for the industrialization upgrading and quality improvement of Vatica wine.

Objective To establish a method for the detection of furosine in milk by microwave hydrolysis-ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Methods The optimal conditions for microwave hydrolysis were optimized by single factor experiments and response surface methodology. The hydrolysis solution obtained under the optimal hydrolysis conditions was filtered to a constant volume. The hydrolysate was diluted 10-fold with 6.0 g/L ammonium acetate solution and then analyzed. Gradient elution was performed with 0.1% formic acid aqueous solution and methanol solution as mobile phases, and the separation was carried out on a T3 liquid chromatography column (100 mm×2.1 mm, 1.8 μm). Under the positive ion mode of electrospray ion source (ESI⁺), multiple reaction monitoring (MRM) mode was selected for detection and external standard method was used for quantification. Results The optimal microwave hydrolysis conditions for furosine in milk were hydrolysis temperature of 160 ℃, hydrochloric acid concentration of 8.1 mol/L, and hydrolysis time of 52 min. The primary-to-secondary order of influencing factors was hydrochloric acid concentration>hydrolysis time>hydrolysis temperature. Furosine in milk showed a good linear relationship within the range of 0.005-0.500 µg/mL, with a correlation coefficient (r) of 0.9958. The limit of quantitation (LOQ) and limit of detection (LOD) were 0.20 µg/mL and 0.07 µg/mL, respectively. The average recoveries were 89.09%-97.33%, with relative standard deviations (RSDs) of 3.37%-7.02% (n=6). Conclusion This method is efficient and accurate. Compared with the traditional hydrolysis methods(12-24 hours), microwave hydrolysis shortens the hydrolysis time to 52 minutes, and there is no significant difference (P>0.05) in the detection results compared with the conventional hydrolysis methods in the industry standard NY/T 939—2016 Identification of reconstituted milk in pasteurized and UHT milk. It can provide technical reference for quality control and heat treatment process evaluation of dairy products.

Objective To establish a method to simultaneously determine the content of 5 kinds of components of Lonicera japonica Thunb. herbs from Sandao real estate area (neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C) by quantitative analysis of multi-components by single marker. Methods Phenomenex Synergi Hydro-RP80A (250 mm×4.6 mm, 4 μm) column was used with acetonitrile (A)-0.1% phosphoric acid aqueous solution (B) as mobile phase, the detection wavelength was 327 nm, the column temperature was 20 ℃, and the flow rate was 0.7 mL/min. The injection volume was 2 µL. Results The linear ranges of neochlorogenic acid, chlorogenic acid, isochlorogenic acid B, isochlorogenic acid A and isochlorogenic acid C were 0.41-16.40, 7.22-289.00, 0.21-8.50, 1.65-66.00 and 0.37-14.80 μg/mL (r≥0.9993), respectively. The average recovery rate was 95.25%-100.42%, and the relative standard deviation (RSD) of precision, repeatability and stability were less than 2.0%. The content of neochlorogenic acid, chlorogenic acid, isochlorogenic acid A, isochlorogenic acid B and isochlorogenic acid C in 25 batches of samples was determined by external standard method, and there was no significant difference between the measured values and the calculated values of quantitative analysis of multi-components by single marker method. Conclusion This method is accurate, reliable and simple for the simultaneous determination of the content of 5 kinds of compounds in Lonicera japonica Thunb., which solves the bottleneck problem of lack of reference substances in the quality control of Lonicera japonica Thunb.. The content of caffeoylquinic acid in Lonicera japonica Thunb. from different origins varies greatly, and it is necessary to further strengthen the processing of Lonicera japonica Thunb.. This study provides an important basis for the identification, quality evaluation and formulation of quality standards of Lonicera japonica Thunb..

Objective To establish a method for the simultaneous determination of 11 kinds of synthetic colorants in beverages by automated solid-phase extraction-liquid chromatography. Methods The 2 g of the beverage sample was taken, it was extracted with an ammonia ethanol solution, and operations such as activation, sample loading, washing, eluting and collection were performed in turn with the help of a fully automatic solid-phase extraction instrument. After nitrogen blowing and redissolution, the liquid chromatography instrument was used for on-line determination [diode multi-wavelength multi-channel simultaneous detection, detection wavelengths 415 nm (citrus yellow and quinoline yellow), 520 nm (new red, amaranth red, carmine, sunset yellow, temptation red, acidic red, and red algae), 610 nm (indigo and bright blue); mobile phase: A 20 mmol/L ammonium acetate solution, B methanol, flow rate 1 mL/min, gradient elution]. Results In the range of 0.2-10.0 μg/mL, the mass concentration of 11 kinds of synthetic colorants showed good linear relationship with peak area, and the linear correlation coefficients were all greater than 0.99, the limit of detection met the requirements of GB 500935—2023 National food safety standard-Determination of synthetic colorants in food. In the standard addition method recovery test, the recovery rates were between 91.3% and 106.0%, and the relative standard deviation of the determination value (n=6) was less than 5.0%. This method was applied to the ability verification of sunset yellow and carmine in beverages in food testing institutions in the Yangtze River Delta. The content of carmine was 5.86 mg/kg, and the content of sunset yellow was 4.31 mg/kg. The other synthetic colorants were not detected. Conclusion This method achieve good enrichment effect, high automation degree, simple operation, good stability, short time, high efficiency, good sensitivity, high accuracy and good reproducibility, and is suitable the determination and analysis of synthetic colorants in a large number of beverages.