A quantitative method for the detection of cashew allergens in foods was established based on ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Cashew samples were extracted, trypsinized, purified, and separated using an Easy nLC 1000 nano-liquid chromatograph, and then data were collected in the full-scan acquisition mode by quadrupole/orbitrap high-resolution mass spectrometry. The scanning results were analyzed by ProteinPilot software search against the UniProt protein database, and the peptide specificity was verified using the basic local alignment search tool (BLAST). Finally, six cashew specific peptides were selected, and actual samples were detected by UPLC-quadrupole/orbitrap MS in the multi-reaction monitoring (MRM) mode. The results showed that the proposed method had good linearity in the range of 0.005‒10 mg/mL with correlation coefficients (R²) greater than 0.99. The quantitation limit was 2.5‒5 mg/kg and 0.005‒0.01 mg/mL for solid-state and beverage matrices, respectively. The average recoveries were 82.5%‒109.9%, and the relative standard deviation (RSD) was not more than 8.9%. This method has high sensitivity and specificity, and it can be used for the detection of cashew allergens in six food substrates including biscuit, bread, cake, walnut cookie, chocolate and beverage.

A new method for rapid screening for and identification of 11 foodborne stimulants and five alkaloids in hot pot soup base seasoning by ultra-high performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) was developed. The analytes from samples were extracted with 80% aqueous acetonitrile, cleaned up on a PRiME HLB column, and separated on a Kinetex F5 column prior to qualitative screening and quantitative analysis in the high-resolution scanning mode using multiple reaction monitoring (MRM). The relative deviations of the exact mass numbers of the 16 compounds were less than 5.0 × 10^-6, and the linearity of the calibration curves was good with correlation coefficient (R²) greater than 0.9970. The recoveries of the analytes were 75.2%–105.4%, with relative standard deviation (RSD) of 1.3%–7.4% (n = 6). The limit of detection (LOD) was 0.05–1.0 µg/kg, and the limit of quantitation (LOQ) was 0.10–2.0 µg/kg. The developed method is simple, rapid, accurate, and practical.

A rapid method for the determination of VA, VD (VD₂, VD₃) and VE (α-, β-, γ-, and δ-vitamin E) in foods for special medical purposes was established using online solid phase extraction (SPE) combined with two-dimensional liquid chromatography (2D-LC). After saponification, enrichment and purification of VA, VD and VE from samples were accomplished on an online SPE cartridge. VA and four VEs were quantitatively analyzed by the first-dimensional LC, and VD was transferred by heart-cutting to the second-dimensional chromatographic system for separation and detection. SPE columns with different fillings, sample loading solvents, and eluent composition were evaluated, and 2D-LC conditions were systematically optimized. Good linearity was achieved for all vitamins tested with correlation coefficients (R²) greater than 0.997. The mean recoveries of the developed method were 84.4%–109.0% with relative standard deviation (RSD) of 0.34%–6.55% (n = 6). This method was highly automated with low detection errors and high detection efficiency, and could be used for the analysis of vitamins in foods for special medical purposes.

An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was established for the detection of pine nut allergen Pin k 2 in food matrices. Pine nuts were ground, degreased, and enzymatically extracted and the hydrolysate was separated and analyzed by using an Easy-nLC 1000-QExecutive high-resolution mass spectrometer, and the mass spectral data obtained were processed using Protein Pilot TM software and the Uniprot protein database. The specificity was verified by Basic Local Alignment Search Tool (BLAST), and three pine nut-specific peptides were selected finally. The developed method exhibited a good linear relationship in the concentration range of 0.001–50 mg/mL, and the limit of quantification was 1 mg/kg. The average recoveries for blank biscuit, chocolate and beverage were 88.50%–107.57%, with a relative standard deviation (RSD) not exceeding 6.08%, and the matrix effect was 89.77%–96.13%. This method has the advantages of high sensitivity and good specificity, and can be applied to the detection of pine nut allergens in food samples such as biscuits, chocolate, and beverages, which provides technical support for the authentication of food labels and the detection of latent allergens in foods.

A new method for screening and identification 420 pesticide residues in fruits and vegetables by ultra-performance liquid chromatography coupled with quadrupole-time of flight mass spectrometry (UPLC-Q-TOF/MS) were developed. The samples were extracted with acetonitrile/acetic acid (99:1, V/V), and clean-up by SinChERS-Nano (single-step, cheap, effective, rugged, safe, nano) column, determined by UPLC-Q-TOF/MS. The accurate mass database and MS/MS database which contains 420 pesticides were established, the automatic retrieval of detection results was carried on according to the accurate mass, retention time, isotope ratio, ion fragment information, and so on. Method verification was performed on leeks samples. The results showed that 420 pesticides had good linearity in the range of 0.1–100 μg/L, and the correlation coeffificients (R²) was greater than 0.990. The limits of detections (LODs) and limits of quantifications (LOQs) of 420 pesticides were in range of 0.05–2.0 and 0.1–5.0 μg/L, respectively. The average spike recoveries at 3 levels were 70.1% to 119.7%, and the relative standard deviations (RSD) were lower than 20% (n = 6). With this method, a survey of pesticide residues was conducted for 110 samples of 10 different fruits and vegetables, which provided scientific data for ensuring pesticide residue safety of the fruits and vegetables consumed daily by the public. This method was simple, sensitive and accurate, and could be used for rapid screening of 420 pesticide residues in fruits and vegetables.