A method combining QuEChERS extraction, ultra-high pressure liquid chromatography and full scan high resolution mass spectrometry was evaluated for its use in screening for chemical residues and contaminants in animal-related food matrices. The method was evaluated by analysis of multiple replicates of whole milk, muscle tissue, liver tissue and corn silage. Analytes tested included plant alkaloids, carbamate and organophosphate pesticides, and several types of veterinary drugs. A database containing the chemical formula for each analyte was used to calculate accurate mass-to-charge ratios for expected pseudo-molecular ions. This information, as well as retention times, was used to identify analytes. Of 118 compounds chosen for analysis, 86 were detectable in all fortified replicates of at least one matrix at levels ranging from 1.0 to 5000 ng/g. Variability of response, as measured in % relative standard deviation of peak areas over seven replicate fortified sample analyses, was found to differ among the classes of analytes, ranging from 100%. Retention times were stable and analytes were routinely detected at measured mass-to-charge ratios within 2 ppm of their theoretical mass-to-charge ratios. These results indicate that the combination of generic extraction and chromatographic procedures with full scan high resolution mass spectrometry can serve as a useful method for screening complex matrices.
Globally, mushroom poisonings cause about 100 human deaths each year, with thousands of people requiring medical assistance. Dogs are also susceptible to mushroom poisonings and require medical assistance. Cyclopeptides, and more specifically amanitins (or amatoxins, here), are the mushroom poison that causes the majority of these deaths. Current methods (predominantly chromatographic, as well as antibody-based) of detecting amatoxins are time-consuming and require expensive equipment. In this work, we demonstrate the utility of the lateral flow immunoassay (LFIA) for the rapid detection of amatoxins in urine samples. The LFIA detects as little as 10 ng/mL of α-amanitin (α-AMA) or γ-AMA, and 100 ng/mL of β-AMA in urine matrices. To demonstrate application of this LFIA for urine analysis, this study examined fortified human urine samples and urine collected from exposed dogs. Urine is sampled directly without the need for any pretreatment, detection from urine is completed in 10 min, and the results are read by eye, without the need for specialized equipment. Analysis of both fortified human urine samples and urine samples collected from intoxicated dogs using the LFIA correlated well with liquid chromatography–mass spectrometry (LC-MS) methods.
3 March 2015 in Journal of Agricultural and Food Chemistry