To establish a method for determining the purine content in prepackaged solid beverages by high performance liquid chromatography and to apply it to the analysis of commercially available ones.

The 4 kinds of purines were extracted from solid beverages using acid hydrolysis. Chromatographic columns were screened based on resolution and peak shape. Detection conditions, including mobile phase pH, flow rate and column temperature, were optimized, and method validation was performed.

Using a Sunniest C₁₈ column, a mobile phase of 10 mmol/L ammonium formate solution at pH 3.68 methanol (99:1, V:V), a flow rate of 1.0 mL/min, a column temperature of 30 ℃, an injection volume of 10 μL, and a detection wavelength of 254 nm, the 4 kinds of purines were completely separated with good peak shapes. Guanine, adenine and hypoxanthine exhibited good linearity in the range of 1–40 mg/L (r²≥0.9990), while xanthine showed good linearity in the range of 0.1–4.0 mg/L(r²=0.9998); the limits of detection were 0.01–0.14 mg/L, and the limits of quantitation were 0.04–0.46 mg/L;spiked recovery rates were 88.00%–113.00%, with relative standard deviations were 0.05%–5.90%. The purine content in the 11 kinds of milk tea samples ranged from 6.66 mg/100 g to 30.46 mg/100 g, and in the 11 kinds of coffee samples, it ranged from 5.28 mg/100 g to 26.11 mg/100 g.

This method exhibits good precision and accuracy and can be used for the simultaneous determination of 4 kinds of purines in solid beverages, providing a scientific basis for dietary choices among individuals with hyperuricemia and gout.

To develop an electrochemiluminescence (ECL) test strip for the detection of aflatoxin B₁(AFB₁).

The ECL test strip was fabricated by patterning carbon ink electrode onto the surface of a polyvinyl chloride substrate and then assembling them with a lateral flow immunoassay strip. The electrochemical performance of the ECL test strip was investigated using cyclic voltammetry. Meanwhile, Ru-PEI/Ti₃C₂T_x@Au composites were synthesized and conjugated with AFB₁ monoclonal antibodies (Anti-AFB₁) to serve as ECL signal probes. Through the competitive immunoreaction between the AFB₁-bovine serum albumin conjugate immobilized on the test line of the ECL test strip and the ECL signal probes, colorimetric and ECL signals were obtained.

The fabricated ECL test strips exhibited good stability and specificity. Under optimal conditions, the colorimetric signal showed a good linear relationship with the logarithm of AFB₁ concentration in the range from 0.1 ng/mL to 100.0 ng/mL, with a limit of detection of 32 pg/mL. In addition, the ECL signal showed a good linear relationship with the logarithm of AFB₁ concentration in the range from 1.0 pg/mL to 100.0 ng/mL, with a limit of detection of 319 fg/mL. Furthermore, satisfactory recovery rates ranging from 92.6% to 110.3% were achieved by the proposed ECL test strips, along with relative standard deviations of 0.9% to 6.2%.

The developed ECL test strip enables highly sensitive and rapid detection of AFB₁ in corn samples, providing a new perspective for rapid mycotoxin detection.

To investigate the comprehensive effects of multiple factors including time, temperature, bacterial strains, initial contamination levels and types of packaged drinking water on the viability of Pseudomonas aeruginosa in packaged drinking water.

Different types of commercially available packaged drinking water samples were artificially contaminated with Pseudomonas aeruginosa strains from various sources at different levels.The concentration changes of Pseudomonas aeruginosa in packaged drinking water under different temperature conditions were continuously monitored using the membrane filtration method and plate count method, and the comprehensive effected of relevant factors on the viability of Pseudomonas aeruginosa in packaged drinking water were analyzed.

In natural mineral water for drinking, the trends of Pseudomonas aeruginosa concentration over time at different temperatures exhibited essential differences. When the initial contamination level was approximately 70 CFU/mL, at 23 ℃ and 30 ℃, the bacterial concentration increased exponentially from the 3rd to 4th day. At 30 °C, the concentration reached 10⁶ CFU/mL on the 3rd day. At 15 ℃, the proliferation was delayed until the 5th to 6th day, with the concentration reaching 10⁶ CFU/mL on the 9th day. In contrast, at 8 ℃, the bacterial concentration showed a continuous slow decline, although it remained detectable (3 CFU/mL) until the 12th day. In purified water for drinking and other drinking water, the concentration of Pseudomonas aeruginosa generally showed a decreasing trend at different temperatures, but the decay rates differed significantly. When the initial contamination level was approximately 70 CFU/mL, in purified water for drinking, Pseudomonas aeruginosa decayed fastest at 8 ℃ and 30 ℃, becoming undetectable (0 CFU/mL)on the 3rd day. At 15 ℃, the decay rate was the slowest, with the concentration falling below the detection limit on the 5th day. At 23 ℃, the decay rate was intermediated between the above two, with the concentration becoming undetectable on the 4th day. In other drinking water, at 30 ℃, Pseudomonas aeruginosa exhibited the fastest decay, becoming undetectable (0 CFU/mL) on the 3rd day. At 15 ℃ and 23 ℃, the decay rate was moderate, with the concentration falling below the detection limit on the 5th day. At 8 ℃, the decay rate was the slowest, with the concentration becoming undetectable on the 7th day. Under identical test conditions, including temperature and type of packaged drinking water, the effects of differences in strain and initial contamination level on the trends of Pseudomonas aeruginosa concentration were generally consistent.

The combined effects of factors including time, temperature and type of packaged drinking water on the viability of Pseudomonas aeruginosa are extremely significant.Nevertheless, despite differences in bacterial strains and initial contamination levels, the changing trends of Pseudomonas aeruginosa viability are generally consistent. The findings of this study will provide more scientific evidence for risk prevention and control in the production, processing, quality control and market consumption stages of packaged drinking water.

To optimize the processing technology of red mud roasted eggs and analyze their volatile flavor compounds.

This study adopted the mud-immersion method, used potassium chloride (KCl) to partially replace sodium chloride (NaCl) and red mud as an auxiliary material. The salt-mud concentration was controlled, and the pickling process was optimized through an orthogonal experiment to develop novel red mud roasted eggs. Gas chromatography-mass spectrometry (GC-MS) and gas chromatography-ion mobility spectrometry (GC-IMS)were utilized to determine the volatile flavor compounds of the products.

The results showed that when the liquor addition was 0.6%, the KCl replacement was 7%, and the salt-mud concentration was 51%, the obtained products exhibited moderate saltiness, a high yolk oil exudation rate and the best sensory quality. GC-MS detection revealed that the relative contents of esters, alcohols and ketones increased after pickling, while the aldehyde components changed. Among them, hexanal, 1-octen-3-ol and furans were the primary flavor contributors. Furthermore, GC-IMS results demonstrated that before pickling, alcohols and straight-chain aldehydes were dominant, presenting a fresh and fruity fragrance; after pickling, esters and branched-chain aldehydes increased, which enhanced the ester and roasted aromas, resulting in a richer flavor profile.

The red mud pickling and roasting process effectively promotes lipid oxidation and the Maillard reaction within the eggs, which transforms the flavor from a light fragrance to a complex flavor. This study not only improves the defects of traditional salted eggs, such as high salt content and unstable quality, but also provides a valuable theoretical reference for the development and promotion of low-sodium and characteristic flavor egg products.

To determine the content of 11 kinds of organic acids (citric acid, malic acid, tartaric acid, succinic acid, maleic acid, lactic acid, acetic acid, tannic acid, fumaric acid, gallic acid and coumaric acid) in green plum wine by high performance liquid chromatography (HPLC) and the chemical pattern recognition analysis is performed.

The analysis was performed using HPLC with a CAPECELL PAK ADME C₁₈ (4.6 mm×250 mm, 5 μm)column, where mobile phase A was methanol and mobile phase B was a 0.1% (V:V) aqueous phosphoric acid solution.Gradient elution was employed at a column temperature of 30 ℃, with a detection wavelength of 210 nm. The results were subsequently analyzed using chemopattern recognition software, specifically SPSS 25.0 and SIMCA 14.1.

The 11 kinds of organic acids exhibited excellent linearity (r≥0.9993) within their respective mass concentration ranges, with average addition recovery ranging from 92.69% to 104.35% and relative standard deviations of 0.29% to 4.72%. Cluster analysis of 9 batchs samples revealed 3 distinct groups when Euclidean distance was set to 5. Principal component analysis identified 3 major components, consistent with cluster results: the first principal component included tartaric acid, malic acid, tannic acid, citric acid, succinic acid and fumaric acid; the second principal component comprised acetic acid and gallic acid; while the third principal component consisted of lactic acid, maleic acid and coumaric acid. Orthogonal partial least squares discriminant analysis identified citric acid and malic acid as potential flavor difference markers.

The method is simple, accurate and sensitive, and is suitable for qualitative and quantitative analysis and evaluation of organic acids in green plum wine and other foods.

To understand the content of trace elements in the livers and kidneys of sheep and pigs sold in some areas of Inner Mongolia and evaluate their safety.

Randomly selected the livers and kidneys of sheep and pigs from the marketplaces and supermarkets in some areas of Inner Mongolia. After microwave digestion, determined the content of lead, cadmium, total arsenic, total mercury, barium, copper, manganese, selenium, chromium and nickel using inductively coupled plasma mass spectrometry. Statistical analysis was conducted, exposure risk assessment was carried out in combination with single-factor pollution index, target hazard index and carcinogenicity index.

There were significant differences in the content of manganese, selenium, copper and cadmium in the kidneys and livers (P<0.05); there were significant differences in copper, total arsenic and selenium in sheep liver and pig liver (P<0.05); there were no significant differences in the content of 10 kinds of elements in sheep kidney and pig kidney (P>0.05). The copper pollution index in sheep liver, the single-factor pollution index of selenium in pig liver and pig kidney were greater than 1, reaching the severe pollution level; the comprehensive pollution index of heavy metals such as Nemerol in pig liver, pig kidney and sheep liver was at a slightly polluted level. The comprehensive pollution index of heavy metal Nemerol in sheep kidneys was 0.59, which was within the safety level. The cumulative target hazard coefficient and carcinogenicity coefficient were both within the safe range.

The overall levels of harmful heavy metal elements in the liver and kidneys of sheep and pigs in the Inner Mongolia region are relatively low, with only 3 samples exceding the cadmium limit. cadmium.The content of trace elements is abundant, but the copper content in the liver and the selenium content in the kidneys are too high, posing potential food safety risks. Further identification of the pollution source is necessary, along with continuous monitoring and risk assessment. By studying the content of trace elements in the liver and kidneys of sheep and pigs in the Inner Mongolia region and evaluating their safety, this research aims to guide people in reasonable dietary combinations and ensure the reasonable intake of trace elements.

To systematically evaluate the pesticide residue levels in fresh Zingiber officinale Roscoe in a region of North China in 2025.

A total of 117 batches of seasonal fresh Zingiber officinale Roscoe were collected from a region in North China. After sample pretreatment, high performance liquid chromatography-triple quadrupole mass spectrometry and gas chromatography were used to simultaneously detect residues of 33 kinds of commonly used insecticides, fungicides and plant growth regulators.

The overall detection rate of the 33 kinds of pesticides was 41.88%, with residues mainly occurring at low concentrations. The pesticide residue levels in all samples did not exceed the limits specified in GB 2763—2026 National food safety standard-Maximum residue limits of pesticides in food. Chlorpyrifos was detected in only 1 batch with a residue level of 0.018 mg/kg, while clothianidin was detected in 34 batches with a maximum residue of 0.190 mg/kg; both were close to the limit value of 0.2 mg/kg but remained within safe limits. Meanwhile, multiple residue occurrence was common, with 23.08% of samples containing 2 or more kinds of pesticides, up to a maximum of 5, but all detected values complied with national limit standards.

The overall level of pesticide residues in Zingiber officinale Roscoe in this region is safe and controllable.None of the 117 batches exceeds national safety limits. To continuously ensure the quality and safety of Zingiber officinale Roscoe, it is recommended to establish further risk assessments targeting key pesticides and combined exposure to scientifically guide prevention and control.

To assess the dietary exposure risk of cyanide in fruits and processed fruit products sold in Jiaxing City in 2025.

The content of cyanide in fruits (expressed as hydrocyanic acid) and processed fruit products was detected by gas chromatography referring to GB 5009.36—2023 National food safety standard-Determination of cyanide in food. The dietary exposure risk was evaluated by using the point assessment model and the hazard quotient method, combined with the average consumption of various foods for residents of different age groups.

A total of 90 fresh fruit samples were analyzed and the overall positive rate was 16.7%, with concentrations ranging from not detected to 0.690 mg/kg and an average of 0.0465 mg/kg. Among the 50 fruit processed products (21 fruit wines, 19 fruit juices and 10 fruit jams), the overall positive rate was 56.0%, with total detected values ranging from ND to 6.98 mg/kg, and an average value of 0.681 mg/kg. The average chronic dietary exposure amounts of cyanide in fruits, fruit juices, fruit wines and fruit jams for different gender and age groups were 0.0514, 1.0200, 1.2300 and 0.0218 μg/kg bw·d, respectively, all of which were lower than the maximum allowable daily intake value of 20 μg/kg bw·d for hydrogen cyanide.

Risk assessment indicates that while the intake risk from processed fruit products is higher than that of fresh fruits, both remain within safe limits. However, due to their lower body weight, children were identified as a sensitive group with relatively higher acute and chronic exposure estimates, warranting specific attention.

To develop a method for the detection of dexamethasone (DMS) in milk by colloidal gold lateral flow assay (CG-LFA).

In this study, active groups were introduced from the hydroxyl groups of DMS to prepare haptens, and complete antigens were prepared by coupling carrier proteins. After animal immunization and cell fusion screening, 3 monoclonal antibodies (mAbs)—mAb 2H1, mAb 1B6 and mAb 2B6—were produced. Finally, the CG-labeled antibodies were immobilized as probes using electrostatic adsorption, establishing a colloidal gold method for detecting DMS in milk.

After evaluation, mAb 1B6 was selected as the optimal antibody to establish CG-LFA, with a cut-off value of 0.20 ng/mL and a half maximal inhibitory concentration (IC₅₀) of 0.07 ng/mL. Moreover, the cross-reactivity with 3 kinds of structurally similar betamethasone(BTM), fluorohydrocortisone (FDC) and hydrocortisone (HDC) ranged from 3.9% to 13.4%, and there was no cross-reactivity with the other common hormones. The recoveries of real samples spiked with DMS were in the range of 92.4%–102.8%, and the limit of detection (LOD) was 0.05 μg/kg.

The DMS established in this study is characterized by simplicity of operation and high sensitivity, which is capable of meeting the requirements for rapid on-site detection of DMS in milk.