To establish a rapid detection method for the residue of the fungicide hexaconazole in food by dispersive liquid-liquid microextraction-high performance liquid chromatography.

A deep eutectic solvent synthesized from fenchyl alcohol, hexanoic acid and acetic acid at a molar ratio of 1:3:4 was used as the supporting solvent to prepare a ferrofluid with self-dispersibility and magnetic responsiveness by incorporating Fe₃O₄ nanoparticles. The prepared ferrofluid served as the extraction solvent for dispersive liquid–liquid microextraction, and hexaconazole was subsequently separated and quantified by high-performance liquid chromatography.

Under the optimal experimental conditions, the detection linear range of this method for hexaconazole was 0.02–2.00 μg/mL, the limit of detection was 0.006 μg/mL, and the relative standard deviation was less than or equal to 8.2%. The recovery rates of samples added to mineral water, tea and fruit juice were 83.9% to 95.6%.

This method is environmental friendly, easy to operate and highly sensitive. It can be effectively applied to the rapid detection of pesticide residues in food, providing a new and effective technical means for food safety testing.

To establish a quantitative analytical method for 17 kinds of triterpenic acid compounds in Poria cocos and investigate their content in samples from different regions.

A high performance liquid chromatography method was developed using an C₁₈ column with gradient elution (acetonitrile-0.1% phosphoric acid solution as the mobile phase). The flow rate was set at 1.0 mL/min, column temperature at 20 ℃, and injection volume at 20 μL. The 17 kinds of triterpenic acid compounds were quantified by wavelength switching mode, and the obtained data were subjected to analysis.

All 17 kinds of compounds exhibited good linearity (r>0.999) within their respective concentration ranges. The spike recovery rates ranged from 80.9% to 92.5%, with relative standard deviations below 5.0%. The limits of detection and limits of quantitation respectively were 0.343–2.839 μg/mL and 1.143–9.462 μg/mL.

The established high performance liquid chromatography method features simple sample pretreatment, high sensitivity, excellent stability and accuracy, making it suitable for the determination of 17 kinds of triterpenic acids in Poria cocos. This study provides a foundational basis for the development and utilization of functional components in Poria cocos.

To establish a method for the simultaneous determination of dexamethasone, betamethasone, florfenicol and florfenicol amine residues in pork and beef by high performance liquid chromatography-tandem mass spectrometry.

The samples were extracted with acetonitrile and purified using the QuEChERS method. Separation was performed on a BEH-C₁₈ column with acetonitrile and ultrapure water as the mobile phase for gradient elution. Qualitative and quantitative analysis was conducted via multiple reaction monitoring under both positive and negative ion scanning modes using the external standard method.

Dexamethasone, betamethasone, florfenicol and florfenicol amine exhibited excellent linearity within the mass concentration range of 0.2–100.0 ng/mL, with correlation coefficients exceeding 0.9990. The recovery rates ranged from 85.1% to 107.5%. The limits of detection (LODs) for dexamethasone were 0.44–0.48 μg/kg and the limits of quantitation (LOQs) were 1.45–1.58 μg/kg. For betamethasone, the LODs were 0.46–0.51 μg/kg and the LOQs were 1.52–1.68 μg/kg. For florfenicol, the LODs were 0.47–0.58 μg/kg and LOQs were 1.55–1.91 μg/kg. For florfenicol amine, the LODs were 0.40–0.45 μg/kg and the LOQs were 1.32–1.49 μg/kg.

This method demonstrates accurate parameter determination, with excellent recovery rates, high precision, and a simple, convenient pretreatment process. It meets the requirements for simultaneous screening and qualitative and quantitative detection of dexamethasone, betamethasone, florfenicol and florfenicol amine residues in pork and beef, thereby providing a reliable tool for routine risk assessment.

To comparatively analyze the differences in phenolic substance content among 3 varieties of Lycium barbarum from different production areas in Ningxia.

A total of 36 Lycium barbarum samples of Ningqi No.1, Ningqi No.7 and Keqi No.608 from different production areas in Ningxia were collected. The differences in the content of flavonoids, phenolic acids, carotenoids and betaine in Lycium barbarum were monitored and analyzed, and identification model of Lycium barbarum from different production areas based on phenolic substances was constructed.

The flavonoids, phenolic acids, carotenoids and betaine in Ningqi No.1 Lycium barbarum from different production areas showed significant differences (P<0.05) among 4 production areas. The content of phenolic substances in the Hongshibao production area was significantly higher than that in other production areas. The flavonoids, carotenoids and betaine in Ningqi 7 Lycium barbarum showed significant differences among the 5 production areas. The content of phenolic substances in the Hongshibao production area was significantly higher than that in the other production areas. The flavonoids, phenolic acids and betaine in Keqi 608 Lycium barbarum showed significant differences among the 3 production areas. The content of phenolic substances in the Zhongning production area was significantly higher than that in other production areas. An identification model of Lycium barbarum from different production areas based on the orthogonal partial least squares discriminant analysis discriminant analysis method was established, and its overall correct discrimination rate was 100%.

There are significant differences in the content of phenolic substances among Lycium barbarum from different production areas in Ningxia. This study provides a reference basis for the development of functional components of Lycium barbarum and the comprehensive quality evaluation of Lycium barbarum from different production areas.

To establish a method for the simultaneous determination of 7 kinds of veterinary drug residues, including ciprofloxacin, enrofloxacin, ofloxacin (3 kinds of fluoroquinolones), chloramphenicol, thiamphenicol, flufenicol (3 kinds of amphenicols) and isometamidium (1 kind of antitrypanosomal drugs) in milk by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Milk samples were extracted by the mixture of acetonitrile and 0.5 mmol/L ammonium formate in methanol (1:1, V:V), purified by n-hexane, dried by nitrogen. The 7 kinds of veterinary drug residues in milk samples were detected by UPLC-MS/MS and quantified by matrix matching external standard method.

The linear range of 7 kinds of veterinary drugs in milk was 1.0–200.0 µg/L with good linearity (r² were all greater than 0.993). The limits of detection were 0.08–0.44 µg/kg, and the limits of quantitation were 0.28–1.46 µg/kg. Milk matrix had an enhanced matrix effect on all 7 kinds of veterinary drugs. The recoveries of 7 kinds of veterinary drugs at low, medium and high concentrations were 47.44%–117.89%, 82.34%–112.84%, 73.15%–117.69%, respectively. The relative standard deviations were 1.46%–8.26%. This method was used to analyze 9 samples of commercially available milk, and no residues of 7 kinds of veterinary drugs were detected in any of them.

This method is highly sensitive and easy to operate, and can meet the rapid and accurate detection requirements of seven kinds of veterinary drugs in milk.

To establish a method for the determination of 6 kinds of quinolone residues (ofloxacin, norfloxacin, lomefloxacin, pefloxacin, enrofloxacin and ciprofloxacin) in eggs by solid-phase extraction combined with liquid chromatography-tandem triple quadrupole mass spectrometry.

Egg samples were extracted with 0.1 mol/L ethylenediaminetetraacetic acid-Mcllvaine (EDTA-Mcllvaine) buffer, purified by HLB solid-phase extraction cartridges and separated on an Acquity BEH C₁₈ column (100 mm×2.1 mm, 1.7 μm) using a gradient elution with methanol-acetonitrile (4:6, V:V) and 0.2% formic acid aqueous solution as the mobile phase. The analytes were detected in positive electrospray ionization (ESI+) mode with multiple reaction monitoring (MRM), quantified using a matrix-matched calibration curve.

The 6 kinds of quinolones exhibited good linearity in the range of 1.0–100.0 μg/kg with correlation coefficients (r²) more than 0.999. The limits of detection and limits of quantitation were 0.13–0.25 μg/kg and 0.43–0.83 μg/kg, respectively. The average recoveries ranged from 94.6% to 108.0%, with relative standard deviations of 2.48%–6.34% (n=3).

The developed method is simple, sensitive and robust, suitable for the rapid detection of quinolone residues in eggs, providing technical support for food safety monitoring.

To understand the distribution characteristics of microorganisms and their pathogenic factors in commercially available foods in Wuxi City from 2012 to 2024.

According to the requirements of the Wuxi food safety risk monitoring work plan for each year, randomly select food products sold in Wuxi for testing, and used the methods recommended in the provincial work manual for each year to inspect the samples.

From 2012 to 2024, a total of 2734 food samples were tested for foodborne pathogens, with a positive detection rate of 11.19%; the 12 kinds of pathogenic bacteria were detected, with Vibrio parahaemolyticus having the highest detection rate (15.81%), followed by Bacillus cereus (10.21%) and Cronobacter genus (7.47%), with statistically significant differences (χ²=577.14, P<0.001); the detection rate was highest in 2015 (17.68%) and lowest in 2020 (2.35%), with a statistically significant difference (χ²=62.59, P<0.001); pathogenic bacteria were detected in 8 kinds of food, with higher detection rates in aquatic products (25.5%) and infant food (14.3%), and the difference was statistically significant (χ²=92.56, P<0.001); in different sampling stages, the detection rate of pathogenic bacteria in super large restaurants in the catering service stage was the highest (25.00%), and the detection rate of pathogenic bacteria in agricultural markets in the circulation stage was the highest (17.54%), with statistical significance (χ²=53.80, P<0.001). The 261 aquatic products were tested for 5 kinds of parasites, with a detection rate of 9.90% for nematodes; jaw mouth nematodes (third stage larvae) were detected in one sample of eels, with a detection rate of 0.80%.

The food sold in Wuxi City is contaminated to some extent by microorganisms, with a diverse distribution of contamination and a phenomenon of mixed contamination.Particularly, the hygiene issues of aquatic products, infant cereal supplementary foods, farmer’s markets and catering units deserve attention. It is recommended to carry out monitoring of key links and key foods, and in the later stage, it is suggested to expand the monitoring scope and samples to prevent the occurrence of foodborne diseases and food poisoning.

To investigate the effect of moderate enzymatic hydrolysis process on the quality of walnut milk.

Walnut milk was treated with flavor protease and alkaline protease (the ratio was 2:1) under different enzymatic hydrolysis times: Blank control (no enzyme), 0 min (enzyme added and immediately inactivated), 30 min, 60 min and 120 min. The nutritional components, physical stability, aroma components and sensory quality of walnut milk were systematically analyzed.

The nutritional components of walnut milk treated under different enzymatic hydrolysis times were different. With the increase of enzymatic hydrolysis time, the content of oligopeptides and free amino acids in the samples increased, reaching the highest levels at 120 min. The stability kinetic index of walnut milk after enzymatic hydrolysis for 30 min was the lowest and the stability was better.Enzymatic hydrolysis improved the aroma characteristics of walnut milk, increasing both the diversity and abundance of volatile compounds. Sensory evaluation showed that enzymatic hydrolysis enhanced the aroma intensity of walnut milk and the mouthfeel became smoother and more delicate, with the 30 min hydrolysate receiving the best overall acceptability.

Enzymatic hydrolysis for 30 min is the optimal time that provides the best overall balance for walnut milk. At this time, the nutritional composition, stability, flavor and sensory quality of walnut milk are improved.

To evaluate the taste and nutritional quality of Songjiang rice by multivariate statistical methods.

This study focused on 2 varieties of Songjiang rice and 3 kinds of other types of rice from distinct geographical origins. Quality indicators including moisture, protein, fat, amylose content, gel consistency, calcium, iron, zinc and selenium were analyzed. Coefficient of variation analysis, correlation analysis, principal component analysis and cluster analysis were employed for a comprehensive evaluation of the rice’s taste and nutritional quality.

The coefficients of variation for quality indicators of the rice ranged from 5.24% to 49.90%. Among these indices, selenium content displayed the greatest variability, while moisture content exhibited the least. Correlation analysis revealed that amylose content showed a significantly, moderately strong negative correlation with gel consistency. Meanwhile, calcium and iron were significantly and moderately strong positive correlated, as were zinc and protein (P<0.05, correlation coefficient |r|>0.5), indicating information overlap among the quality indicators. Principal component analysis reduced 9 indicators into 3 independent principal components, which together accounted for 71.04% of the cumulative variance. The comprehensive scores for taste and nutritional quality were ranked in descending order as follows: Songxiangjing 1013, Chongming rice, Songxiangjing 1018, Sheyang rice and Wuchang rice. Among these, the Songxiangjing 1013 rice showed outstanding overall quality performance.

The study effectively demonstrates the variations in taste and nutritional quality of rice from different producing regions and different varieties. It establishes a data foundation for the quality evaluation of Songjiang rice and provides theoretical references for rice variety selection, promotion and regional cultivation planning.

To establish an inductively coupled plasma mass spectrometry (ICP-MS) for the determination of 19 kinds of elements in Plukenetia volubilis Linneo, evaluate the elemental distribution characteristics and quality differences of quality variance element of Plukenetia volubilis Linneo from different producing areas.

A total of 33 batches of Plukenetia volubilis Linneo samples from Xishuangbanna,Honghe, Puer (Yunnan Province), Thailand and Laos were subjected to microwave digestion. The content of 19 kinds of elements including Co, Ni and As were determined by ICP-MS. The method validity was verified by linear relationship, precision, repeatability and recovery rate, and principal component analysis and correlation analysis were performed.

The method showed good linearity (r²>0.9990), excellent precision (relative standard deviation<2%) and reliable accuracy (spiked recovery rate: 90.3%–116.8%). The cumulative variance contribution rate of principal component analysis reached 82.854%, and the characteristic elements of Plukenetia volubilis Linneo were identified as Zn, Cd, Sr, Mn, Cr, Pb and Ti. Correlation analysis indicated strong correlations among the elements.

The ICP-MS method can accurately and rapidly determine the content of 19 kinds of elements in Plukenetia volubilis Linneo, providing a reliable approach for evaluating the quality of Plukenetia volubilis Linneo from different producing areas. The analysis of characteristic elements also offers important reference for improving the quality standards of Plukenetia volubilis Linneo.