To establish a method for the simultaneous detection of 154 kinds of pesticides and their metabolites in roasted coffee by liquid chromatography-quadrupole/linear ion trap mass spectrometry.

The samples were extracted with 1% acetic acid in acetonitrile, followed by salting-out and dehydration using sodium chloride and anhydrous magnesium sulfate. The lipids in the extract were then removed with the enhanced lipid removal product Bond Elut EMR-Lipid. Further purification was performed using Carbon S and primary secondary amine (PSA) solid-phase sorbents. Analysis was carried out via multiple reaction monitoring, information-dependent acquisition and enhanced product ion (EPI) scanning, combined with library searching against the EPI spectral library of 154 kinds of pesticides in a multi-step mode. Matrix-matched external standard method was adopted for quantitative determination.

The linear relationship of 154 kinds of pesticides was good linearity with in the range of 2–200 ng/mL (r>0.990). At the spiked levels of 0.01, 0.05 and 0.10 mg/kg, the average recovery rates were 70.4%–117.5%. The relative standard deviations (RSDs, n=6) were 1.7%–14.9%. The limits of detection and limits of quantitation of the method were 0.07–3.00 µg/kg and 0.25–10.00 µg/kg, respectively. The method was accurate and effective. It complied with the testing requirements for pesticide residue limits in China, the European Union and Japan.

This method is simple, rapid and reliable, and can be used for the rapid screening and quantitative analysis of 154 kinds of pesticide residues in roasted coffee.

To establish a rapid and efficient method for the determination of 12 kinds of organophosphate esters (OPEs) in meat products by cold-induced pretreatment combined with high performance liquid chromatography-tandem mass spectrometry.

Freeze-dried meat samples were extracted with acetonitrile and then purified using C₁₈ and N-propylethylenediamine (PSA) adsorbents; further, the acetonitrile/water ratio of the solution was adjusted to 35:65 (V:V) and then the solution was frozen in a −20 ℃refrigerator to separate and enrich OPEs. The target compounds were quantified using high performance liquid chromatography-tandem mass spectrometry coupled with stable isotope internal standards. The cold-induced procedure was optimized and the linear relation, limits of detection, recovery, precision and matrix effect of the method were validated.

Standard solutions exhibited excellent linearity across 0.1–100.0 ng/mL. The correlation coefficients (r) were all greater than or equal to 0.9993. For the tested 12 kinds of OPEs, the average recovery rates at spiking levels of 1 ng/g and 5 ng/g ranged from 82.6% to 115.9%, with relative standard deviations of lower than or equal to 15.9%. The limits of detection for OPEs ranged from 0.1 to 19.2 pg/g, while the limits of quantitation ranged from 0.2 to 64.0 pg/g. The established method was used for the measurement of fresh and pre-cooked meats and OPEs were ubiquitous in the tested real samples. Moreover, the contamination levels of OPEs in pre-cooked foods were much higher than that in fresh foods.

The established analytical method is simple, rapid and highly sensitive; and only a small quantity of reagents and consumables is needed, making it suitable for monitoring large-scale food samples.

To investigate the effects of Asparagus powder on the quality and flavor of cookies.

Single-factor experiments and orthogonal experiments were conducted to determine the optimal formula of Asparagus cookies. Using low-gluten flour cookies as the control, the physicochemical properties, sensory quality, and flavor of both groups were evaluated. Furthermore, solid-phase microextraction coupled with gas chromatography-mass spectrometry was employed for the analysis of volatile flavor components.

Under the temperature-controlled baking condition (preheating the oven to 170 ℃, baking for 8 min, then cooling to 120 ℃and baking for another 12 min), the optimal formula of Asparagus cookies was determined as follows: Asparagus powder 6 g, low-gluten flour 120 g, butter 37.5 g, corn oil 25 g, sunflower oil 12.5 g, milk 24 g, corn starch 4 g, powdered sugar 33 g and salt 1 g. A total of 32 kinds of volatile flavor compounds were detected in the Asparagus cookies, whereas 21 kinds of were identified in the control group (low-gluten flour cookies). Compared with the control group, several unique flavor substances were exclusively found in the Asparagus cookies, including trans-geranylgeraniol (fruity aroma), 1-octen-3-ol (mushroom aroma) and trans-2-heptenal (grassy aroma).

The addition of an appropriate amount of Asparagus powder to low-gluten flour effectively enhances the flavor profile of cookies. This study demonstrates that Asparagus powder can serve as a functional and flavor-enhancing ingredient in baked goods.

To understand the residues and dissipation dynamics of pyrethroid insecticides in Prunus persica L. fruits from the Xiaogan City and assess their dietary intake risk.

Prunus persica L. fruit samples were homogenized, and the target compounds were extracted using acetonitrile as the extraction solvent. The extracts were purified using a combination of primary secondary amine and Florisil. Chromatographic separation was performed on an RTX-5 capillary column (30 m×0.25 mm, 0.25 μm), and detection was carried out using an electron capture detector. Quantification was achieved by the external standard method to determine the residue levels in fruits at 0–23 days after application under different dilution treatments.

Method validation results showed that the 4 kinds of pyrethroid insecticides exhibited good linearity within the concentration range of 0.01–1.00 mg/kg (r²≥0.9942). The average recoveries ranged from 78.85% to 97.62%, with relative standard deviations between 2.12% and 6.85%. The limits of detection and limits of quantitation were 0.001 mg/kg and 0.003 mg/kg, respectively, indicating that the method possesses satisfactory sensitivity and accuracy. Field trial results demonstrated that the residue levels of the 4 kinds of insecticides in peach fruits decreased significantly over time, following first-order kinetic dissipation patterns, with half-lives ranging from 2.60 to 12.95 days. The initial residue concentration increased significantly with higher application concentrations. Residues decreased to 20%–40% of the initial values by day 5 after application, and most treatments showed residue levels below 0.50 mg/kg at 16–23 days, meeting the pre-harvest interval requirements for food safety. Dietary risk assessment indicated that the national estimated daily intakes of the 4 kinds of pesticides under different dilution treatments were substantially lower than their corresponding acceptable daily intakes. The risk quotients ranged from 0.002 to 0.103 (all<1).

Under regular application concentrations and harvest interval conditions, the health risk to consumers is relatively low. Based on the dissipation kinetic data, it is recommended that for the rapidly degrading fenpropathrin and lambda-cyhalothrin, the pre-harvest interval should be no less than 16 days; for the more persistent beta-cypermethrin and deltamethrin, the interval should be extended to 23 days. This study provides important scientific evidence for the safe application of pyrethroid insecticides in Prunus persica L. orchards in the Xiaogan City and offers technical support for their scientific use and management.

To establish a method for the detection of gamithromycin residues in Oryctolagus cuniculus meat by ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

Oryctolagus cuniculus meat samples were extracted using acetonitrile, subjected to defatting with n-hexane, and further purified with Qasis MCX solid-phase extraction cartridges, and analyzed by Xevo TQ-XS UPLC-MS/MS with gradient elution, electrospray ionization positive scan mode (ESI⁺), multiple reaction monitoring(MRM) and internal standard method were applied for quantitative analysis.

There was an excellent linear correlation between the target peak area and the injection mass concentrations of gamithromycin at the range of 0.25–50.00 ng/mL (r²>0.999). The limit of detection and limit of quantitation were 0.25 μg/kg and 0.50 μg/kg. The average recoveries ranged from 76.8% to 102.3%, with intra-batch and inter-batch relative standard deviations both lower than 15% (n=6) at the addition levels of 0.5, 1.0 and 50.0 μg/kg.

The method is sensitive, accurate, and suitable for the detection of residues of gamithromycin in Oryctolagus cuniculus meat. This study can provide scientific basis and technical support for the monitoring and quality safety control of veterinary drug residues in Oryctolagus cuniculus meat products.

To explore an efficient method for extracting messenger RNA (mRNA) from yeast and establish a specific detection method by reverse transcription real-time fluorescence quantitative polymerase chain reaction (RT-qPCR).

A high-performance silica magnetic beads by self-developed were used as carrier, an efficient yeast mRNA extraction technique was developed by combining streptavidin magnetic beads (SM) conjugated with Oligo(dT) and Trizol lysis, followed by optimization of magnetic bead concentration and magnetic adsorption time. Primers based on the yeast chitin synthase 2 (CHS2) gene, established a yeast-specific RT-qPCR assay, and its specificity and stability were validated.

Under optimized extraction conditions, the method enabled extraction yeast mRNA from various concentration, yielded 2.13 μg mRNA even from a low-concentration (2×10³ cfu/mL). This yeast detection methodexhibited a wide linear range from 2×10³ to 2×10⁷ cfu/mL, with a linear equation of Y=–1.69X+33.412 (r²=0.9966), the method exhibited high specificity for the target yeast.

This study successfully establish a mRNA extraction technique by yeast-specific magnetic bead-based and a RT-qPCR detection method, exhibits good specificity and sensitivity, provide a new technology for the detection of yeast contamination in food and scientific research.

To systematically investigate the dynamic variation patterns of major chemical components in Coffea arabica L. under different roasting degrees.

The 3 kinds of Coffea arabica L.beans—Catimor coffee, Caturra coffee and Sachimor coffee—were selected as research the subjects. The content of caffeine, free amino acids, polyphenols, total flavonoids, polysaccharides and chlorogenic acid in raw beans and 6 kinds of roasted bean samples: Yellow dot roasted, cassia bark roasted, light roasted, medium roasted, medium-dark roasted and fully roasted were measured respectively, and the variation patterns of each component with roasting degree were systematically analyzed.

The main chemical component content of the 3 kinds of Coffea arabica L. exhibited the following variation patterns with increasing roasting degree: The caffeine content remained largely unchanged, stabilizing within the range of 0.99%–1.24%; the free amino acid content showed a significant decline, with Catimor coffee decreasing from 0.49% to 0.02%, Caturra coffee from 0.41% to 0.03%, and Sachimor coffee from 0.59% to 0.03%; although the polyphenol content exhibited slight fluctuations during certain roasting stages, it showed an overall declining trend across all 3 kinds of Coffea arabica L. samples as roasting intensity increased, raw beans from 8.27%–8.52% to 5.76%–4.15%; the total flavonoid content showed a pronounced downward trend, dropping from 5.86%–6.88% to 0.95%–1.32%; the polysaccharide content followed a “first decrease followed by significant increase” pattern, from the raw bean stage to the cassia bark roasting stage, the polysaccharide content decreased from 3.47%–4.42% to 2.30%–2.94%. Starting from the light roasting stage, the polysaccharide content increased significantly with increasing roasting degree, reaching 5.84%–7.80% during deep roasting; the total chlorogenic acid content in raw beans reached 64.83–66.12 mg/g, gradually declining to 4.62–7.50 mg/g with increased roasting degree, accounting for only 7.1%–11.3% of the corresponding raw bean content.

This study clarify the quantitative correlation between roasting degree and the main chemical components of 3 kinds of Coffea arabica L. varieties. The findings provide basic data reference for the optimization of Coffea arabica L. roasting processes and the development of functional Coffea arabica L. products.

To establish an analytical method for the determination of content and migration of silver in silver-loaded silicone rubber products by inductively coupled plasma mass spectrometry.

The 3 mL nitric acid and 2 mL hydrofluoric acid were used as digestion acid for pretreatment of silver content, which were digested by microwave digestion method. The migration was simulated with 0.07 mol/L hydrochloric acid solution,4% acetic acid and artificial saliva. After shaking at 40 ℃ for 24 h, the immersion solution was filtered, and the quantitative analysis was performed by inductively coupled plasma mass spectrometry.

The silver content had good linearity in the mass concentration range of 0–100 μg/L, the correlation coefficient (r) was 1.0000, the limit of detection was 0.0009 mg/kg, the limit of quantitation was 0.0029 mg/kg, and the recovery rates were 95.5%–102.2%. The relative standard deviations (RSDs) were 0.92%–2.25%. In 0.07 mol/L hydrochloric acid solution, 4% acetic acid solution and artificial saliva mimics, silver had good linearity in the mass concentration range of 0–100 μg/L, and the correlation coefficients (r) were greater than 0.9995. The limits of detection were 0.0002, 0.0012 and 0.0024 mg/kg, respectively. The limits of quantitation were 0.0006, 0.0036 and 0.0077 mg/kg, the recoveries were 92.3%–101.8%, and the RSD was 1.03%–2.67%. The total silver content of 22 samples was not detected to 9.76 mg/kg, and the detection rate was 81.8%. The migration results of 4% acetic acid solution, 0.07 mol/L hydrochloric acid solution and artificial saliva were not detected to 0.0767 mg/kg, not detected to 0.1061 mg/kg and not detected to 0.0270 mg/kg, respectively, and the detection rates were 22.7%, 45.5% and 9.1%, respectively.

This method is convenient, sensitive, accreted and is suitable for quantitative analysis of total content and migration of silver in silicone rubber.