Search

Although filtration is one of the most common steps in sample preparation for chemical analysis, filter membrane materials can leach contaminants and/or retain some analytes in the filtered solutions. In multiclass, multiresidue analysis of veterinary drugs, it is challenging to find one type of filter membrane that does not retain at least some of the analytes before injection in ultrahigh‐performance liquid chromatography‐tandem mass spectrometry (UHPLC‐MS/MS). In this study, different filter membranes were tested for use in UHPLC‐MS/MS analysis of 183 diverse drugs in bovine muscle, kidney, and liver tissues. Membranes evaluated consisted of polytetrafluoroethylene (PTFE), polyvinylidene difluoride (PVDF), polyethersulfone, nylon, and regenerated cellulose. Drug classes represented among the analytes included β‐agonists, β‐lactams, anthelmintics, macrolides, tetracyclines, sulfonamides, tranquilizers, (fluoro)quinolones, anti‐inflammatories, nitroimidazoles, coccidiostats, phenicols, and others. Although the presence of a matrix helped reduce the binding of analytes on surface active sites, all of the filter types partially retained at least some of the drugs in the final extracts. In testing by flow‐injection analysis, all of the membrane filters were also observed to leach interfering components. Ultimately, filtration was avoided altogether in the final sample preparation approach known as the quick, easy, cheap, effective, rugged, safe, efficient, and robust (QuEChERSER) mega‐method, and ultracentrifugation was chosen as an alternative. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Evidence has emerged that the antioxidant ergothioneine may be important in preventing many inflammatory diseases in humans. However, ergothioneine is not produced by humans or plants and is only made by fungi and some bacteria in soils. As such, humans get ergothioneine from eating fungi (mushrooms) or plants that take it up from the soil. In this study, we found that growing plants with beneficial fungi called arbuscular mycorrhizal fungi increased the amount of ergothioneine in plant tissues. This suggests that promoting agricultural practices that maintain healthy populations of beneficial soil fungi may improve the nutritional quality of crops. Summary: The amino acid ergothioneine (ERGO) has recently gained attention as an antioxidant that benefits human health. ERGO is produced by fungi and mycobacteria in soils and is acquired only from diet. The mechanism by which ERGO is transferred from soil to plant is unknown. Recent work has shown that tillage reduces the amount of ERGO in crops. As tillage also reduces arbuscular mycorrhizal fungi (AMF) populations, we examined the relationship between AMF and plant ERGO uptake.We grew asparagus, black beans, wheat, and oats with a variety of single and mixed species AMF inocula and compared ERGO levels of these plants to plants that were uninoculated.Mycorrhizal inoculation enhanced ERGO content across all plants. There was a positive correlation between AMF colonization level and plant ERGO content.AMF appear to be important mediators of plant ERGO uptake. Future research is needed to identify the mechanism that leads to higher ERGO in plants colonized by AMF in order to promote farming practices that enhance AMF populations and increase crop ERGO concentration in field settings. [ABSTRACT FROM AUTHOR]

The way to maximize scope of analysis, sample throughput, and laboratory efficiency in the monitoring of veterinary drug residues in food animals is to determine as many analytes as possible as fast as possible in as few methods as possible. Capital and overhead expenses are also reduced by using fewer instruments in the overall monitoring scheme. Traditionally, the highly polar aminoglycoside antibiotics require different chromatographic conditions from other classes of drugs, but in this work, we demonstrate that an ion-pairing reagent (sodium 1-heptanesulfonate) added to the combined final extracts from two sample preparation methods attains good separation of 174 targeted drugs, including 9 aminoglycosides, in the same 10.5-min ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. The full method was validated in bovine kidney, liver, and muscle tissues according to US regulatory protocols, and 137-146 (79-84%) of the drugs gave between 70 and 120% average recoveries with ≤ 25% RSDs in the different types of tissues spiked at 0.5, 1, and 2 times the regulatory levels of interest (10-1000 ng/g depending on the drug). This method increases sample throughput and the possible number of drugs monitored in the US National Residue Program, and requires only one UHPLC-MS/MS method and instrument for analysis rather than two by the previous scheme. [ABSTRACT FROM AUTHOR]

Abstract: A liquid chromatographic-tandem mass spectrometric (LC–MS/MS) multi-residue method for the simultaneous quantification and identification of 38 residues of the most widely used anthelmintic veterinary drugs (including benzimidazoles, macrocyclic lactones, and flukicides) in milk and liver has been developed and validated. For sample preparation, we used a simple modification of the QuEChERS method, which was initially developed for pesticide residue analysis. The method involved extracting sample (10g) with acetonitrile (10mL), followed by phase separation from water (salting out) with MgSO4:NaCl (4:1, w/w). After centrifugation, an aliquot of the extract (1mL) was purified by dispersive solid-phase extraction with MgSO4 (150mg) and C18 (50mg), prior to LC–MS/MS analysis. Two injections of the same extract were required with the LC–MS/MS instrument to cover the 30 electrospray positive and 8 electrospray negative analytes. The limit of quantitation of the method was 5μgkg−1 for 37 analytes (and 10μgkg−1 for dichlorvos). The method was successfully validated according to the 2002/657/EC guidelines. Recovery of analytes was typically in the 70–120% range, with repeatabilities and reproducibilities typically <15% in milk and <20% in liver. [Copyright &y& Elsevier]