An ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for simultaneous determination of 10 mycotoxins in grain was developed. The selected mycotoxins were: deoxynivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, fusarenon X, moniliformin, zearalenone, zearalanone, ochratoxin A and ochratoxin B. The samples were extracted with aqueous acetonitrile (84 : 16, v/v) and purified by reliable laboratory-made mixed cartridges. The analytes were separated on an Acquity UPLC HSS T3 column (100 × 2.1 mm, 1.8 µm) and eluted with a mobile phase of water containing 0.2% aqueous ammonia and acetonitrile/methanol (90 : 10, v/v). All mycotoxins were detected with a Waters Micromass Quattro Ultima Pt tandem quadrupole mass spectrometer operating in negative electrospray ionization using multiple reaction monitoring mode. Accurate determination was achieved by employing commercial ¹³C₁₅-deoxynivalenol as internal standard, which compensated for target loss and eliminated matrix effects. The established method was further validated by determining the linearity (R ²> 0.9990), average recovery (75.8–106.5%), sensitivity (limit of quantitation 0.09–8.48 µg kg⁻¹) and precision (relative standard deviation ≤ 6.9%). It was shown to be a suitable method for simultaneous determination of 10 mycotoxins in grain. Finally, a total of 69 corn samples randomly collected from eastern and northern China were analyzed. The results showed that deoxynivalenol was the most frequently detected contaminant, whilst 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, zearalenone, zearalanone, fusarenon X and moniliformin also occurred frequently. Ochratoxin A and ochratoxin B were present only in trace amounts in a small number of samples.

Fraud in milk and dairy products occurs when cow milk is added to sheep and goat milk for economic reasons. No reliable, selective, and sensitive method exists for quantifying the milk percentage of different species. This work reports the development and validation of a proteomics-based method for the qualitative detection and quantitative determination of cow, sheep, and goat milks in the raw materials used for dairy products. β-Lactoglobulin was selected as the protein marker because it is a major protein in milk and whey powder. The tryptic peptides LSFNPTQLEEQCHI and LAFNPTQLEGQCHV were used as signature peptides for cow milk and for sheep and goat milks, respectively. The winged peptides LKALPMHIRLSFNPTQL*EEQCHI* and LKALPMHIRLAFNPTQL*EGQCHV* were designed and synthesized as internal standards. Validation of the method showed that it has good sensitivity, specificity, reproducibility, precision, and accuracy. This method is easily applicable in routine laboratory analysis without intensive proteomics background.