Direct multiclass desorption electrospray ionization-tandem mass spectrometry method for the analysis of sleep inducers and ototoxic drugs in dried blood spots.

RATIONALE: An unconventional and innovative approach for the quantitative determination of 11 ototoxic and narcoleptic drugs in whole blood is described. The multiclass method allows the inclusion of the most widespread drugs on the market (antihistamines, antidepressants, antihypertensives, anxiolytics, opioids, Z-drugs) responsible for 10% of occupational accidents. METHODS: The developed procedure involved the use of the desorption electrospray ionization (DESI) interface for the direct analysis of dried blood spots (DBS). All the issues strictly connected to the chemical-physical characteristics of DBS and DESI (sample inhomogeneity, DBS support, DESI geometry and solvent) were carefully evaluated and innovative strategies were applied. Haematocrit was managed using a small and measured volume of blood (2 µL) with analysis of the entire DBS. RESULTS: The proposed method was fully validated in terms of limits of detection, limits of quantitation (LOQs; between 60 pg/mm2 and 1.6 ng/mm2 ), linearity (one order of magnitude starting from LOQs) and inter- and intra-day precision (on three levels, with relative standard deviation values not exceeding 17%). Accuracy was calculated by comparison with an ultrahigh-performance liquid chromatography-tandem mass spectrometry method (suitable also as a confirmatory method). CONCLUSIONS: Results showed a surprising sensitivity, demonstrating that this procedure could be suitable for applications in various fields, e.g. forensic analysis. Moreover, as a collateral benefit, it was discovered that the method is able to analyse very light traces left on plastic and glass surfaces by detached dried blood.

A 'Dilute and Shoot' Liquid Chromatography-Mass Spectrometry Method for Multiclass Drug Analysis in Pre-Cut Dried Blood Spots.

Drugs able to affect the auditory and nervous systems and consumed by workers to treatdifferent pathologies can represent a possible source of risk in the work environment. All the target compounds involved in the presented project show ototoxic and/or narcoleptic side effects and, for these reasons, occupational safety organizations have recognized them as potential causes of work injuries. A multiclass method for the analysis of 15 drugs among the most widespread worldwide (belonging to nine different classes including antihistamines, beta-blockers, antidepressants, Z-drugs and opioids), was developed and validated. This study describes a rapid, sensitive and effective method to analyse these substances in whole blood using tailored pre-cut dried blood spots. Detection was achieved with a triple quadrupole mass spectrometer after an easy and simple 'dilute and shoot' solubilisation followed by an UPLC separation. All the issues linked to the use of the dried blood spots and whole blood, such as haematocrit variability, volumetric evaluation and sample carrier choice were carefully studied and managed during method development. From the validation study results it emerged that this approach can be deemed successful thanks to its few pg µL-1 LOQs, good linear intervals, absolute recoveries of no less than 75%, an almost negligible matrix effect and accuracy and precision in line with the European and American guidelines for validation. All the obtained goals have been specifically pursued in order to encourage method diffusion as a primary prevention intervention, even in small private workplaces.

Subcritical water extraction of thyreostats from bovine muscle followed by liquid chromatography-tandem mass spectrometry.

Thyreostats can be used fraudulently to promote a rapid increase in weight of breeding animals at low cost. Their severe toxicological effects impose the development of reliable analytical methods to be used in monitoring plans. This work describes an alternative approach to isolate residues of thiouracil, methyl-thiouracil, propyl-thiouracil, phenyl-thiouracil, tapazole and mercaptobenzimidazole from bovine muscle tissue. The developed procedure is based on the following three steps: i) matrix solid-phase dispersion with C18 for the preliminary sample preparation; ii) subcritical water extraction (SWE) at 160°C and 100 bar; iii) clean-up on an Oasis HLB cartridge. The quantitative determination was performed by LC-MS/MS in dual polarity ionization by using internal standardization. The SWE-LC-MS/MS method was validated according to the identification criteria of the Commission decision 2002/657/EC. The relative recoveries ranged from 72 to 97%; within-lab reproducibility was less than 18%. The decision limit and the detection capability of all analytes were below the recommended concentration, set at 10 µg kg-1, but the validation results demonstrated that this method could only be applied for screening of thiouracil and methyl-thiouracil. Besides the analytical advantages related to the use of water as solvent extraction, the procedure allowed significant removal of lipids, whose detrimental effects on instrumentation and MS sensitivity are well-known.

Ambient mass spectrometry: Direct analysis of dimethoate, tebuconazole, and trifloxystrobin on olive and vine leaves by desorption electrospray ionization interface.

A new field of application for a relatively new mass-spectrometric interface such as desorption electrospray ionization was evaluated. For this purpose, its behavior was tested versus quantitative analysis of dimethoate, trifloxystrobin, and tebuconazole directly on olive and vine leaves surface. The goal was workers exposure assessment during field re-entry operations since evidence suggests an association between chronic occupational exposure to some agrochemicals and severe adverse effects. Desorption electrospray ionization gave good response working in positive ionization mode, while numerous test were necessary for the choice of a unique blend of spray solvents suitable for all 3 substances. The best compromise, in terms of signal to noise ratios, was obtained with the CH3 OH/H2 O (80:20) mixture. The obvious difficulties related to the impossibility to use the internal standard were overcome through an accurate validation. Limits of detection and quantitation, dynamic ranges, matrix effects, and intraday precisions were calculated, and a small monitoring campaign was arranged to test method applicability and to evaluate potential dermal exposure. This protocol was developed in work safety field, but after a brief investigation, it was find to be suitable also for food residue evaluation.

Recent advancements and future trends in environmental analysis: Sample preparation, liquid chromatography and mass spectrometry.

Among the thousands of chemicals having potential to enter the environment, the NORMAN network has identified at least 700 substances categorized into 20 classes in the European surface waters. Pesticides, pharmaceuticals, disinfection by-products, wood preservation and industrial chemicals are the prominent classes. Since the impact of these substances on aquatic life and human health might be dramatic, action is urgently required at multiple levels; one of them is just related to the development of more and more sensible and selective analytical methods. This review highlights the latest advancements and trends in liquid chromatography-mass spectrometry based environmental analysis. Specific sections are dedicated to novelties in sample preparation, chromatographic separation and mass spectrometry detection of emerging pollutants. The review also offers insights on last generation chromatographic and extraction materials, technological progresses and innovative methodological approaches for target and non-target analysis. As numerous papers have been published in this field, this overview covers the most representative and original works published in the 2011-2016 period.

Veterinary drugs residues: a review of the latest analytical research on sample preparation and LC-MS based methods.

The world population is increasing and there is a growing demand for food, leading to intensification of farming methods and a requirement for more coadjuvants. Potential high profits sometimes lead to fraudulent use of drugs and pesticides. Veterinary drugs in particular can pose a real risk to human health if their residues are allowed to enter the food chain. Parent drugs and their metabolites can occur in foodstuffs individually or as multicomponent mixtures with enhanced adverse effects. In order to protect consumer safety, the European Union has established lists of forbidden substances, maximum residue limits for authorised drugs and precise criteria for confirmation analyses and interpretation of the results. Due to their nature and potential danger, the 'best available technique' should always be applied. Following this principle, this review examines the procedures and techniques applied to monitoring pharmaceutical products of major concern (e.g. anthelmintics, NSAIDs, corticosteroids, coccidiostats) in foods of animal origin, discussing advances over the past five years and future trends in the field of food safety. Our goal was both to focus attention on this important topic and to provide a selection of the most relevant recent papers on drug residues in foodstuffs.

Residue analysis of thyreostats in baby foods via matrix solid phase dispersion and liquid chromatography - dual-polarity electrospray - tandem mass spectrometry.

This paper describes a rapid method for confirming residues of thyreostats in meat-based baby foods by using liquid chromatography - dual polarity electrospray - tandem mass spectrometry (LC-ES(±)-MS/MS). Six thioureylenes, belonging to the group of thiouracil and imidazole, were selected for this work: thiouracil (TU), methylthiouracil (MTU), propylthiouracil (PTU), phenylthiouracil (PhTU), mercaptobenzimidazole (MBI) and tapazole (TAP). The amphoteric nature of these compounds allows their electrospray detection in both positive and negative ionisation. Nevertheless, MS detection is not favoured by their low molecular weights, while their chromatographic retention is also thwarted by their high polarity. A pentafluorophenyl (PFP) core-shell phase column was selected to avoid peak asymmetry or peak splitting, and a dual-polarity ionisation method was optimised to obtain a sensitivity as high as possible. The method was validated according to the Commission Decision 657/2002/EC. A simple and fast procedure based on matrix solid phase dispersion (MSPD) was optimised to extract analytes from baby foods with recoveries exceeding 82%. Limit of decision (CCα) and detection capability (CCß) were lower than the permissible maximum concentration (10 ng g-1). The validated method was then applied to assess the potential occurrence of the six selected thyreostats in nine commercial products. All the samples were found free of contamination.

Dispersive solid-phase extraction procedure coupled to UPLC-ESI-MS/MS analysis for the simultaneous determination of thirteen cytotoxic drugs in human urine.

A fast and easy tailored dispersive solid-phase extraction (d-SPE) procedure has been developed for the determination of 13 cytostatic drugs. Combined with a rapid and simultaneous ultra performance liquid chromatography/tandem mass spectrometry method for residue identification and quantification in urine, it has been fully validated and tested to study a realistic situation in working environment. The target compounds were chosen from the most common classes used in hospitals. The d-SPE adsorbent was obtained mixing Oasis HLB® with C18 and applied to a large volume of sample (10 mL). The electrospray ionization-mass spectrometry acquisition was conducted in a mixed period mode: six acquisition windows were in positive ionization and one in negative (for 5-fluorouracil). The lowest limit of quantification was found at 0.04 µg/L urine for methotrexate. The absolute recovery of cytotoxic drugs was assessed at two concentrations levels and ranged from 67.1% (cytarabine) to 102.3% (etoposide) and from 65.3% (cytarabine) to 101.2% (methotrexate) for the lower and higher levels, respectively, with the relative standard deviation always <12%. This method gives the opportunity to analyze drugs in a wide molecular weight range (from 130 to 853 a.m.u.) and in a complex matrix, such as urine, without losing any of the features that a method intended for trace quantification must have. Copyright © 2016 John Wiley & Sons, Ltd.

Micro extraction by packed sorbent coupled to liquid chromatography tandem mass spectrometry for the rapid and sensitive determination of cannabinoids in oral fluids.

The evaluation of oral fluids (OFs) levels is useful in proving drug consumption, particularly for monitoring abuse in workplaces and for the driving under the influence of drugs (DUIDs) programs. OF is a complex matrix and a small amount of sample is available, especially after cannabis smoking. This paper reports a method for the determination of cannabinoids and metabolites in OF: THC, 11-hydroxy-THC (OH-THC) and THC-COOH. Cannabidiol (CBD) and cannabinol (CBN) were also detected by LC-MS/MS. The OF pre-treatment was based on micro-extraction by packed sorbent (MEPS), a recently developed solid phase extraction technique which operates with small sample volumes: only 125µL of sample was required, allowing the collection by simple expectoration. Analytes elution was achieved using 2×25µL of 50mM NH4OH in methanol. A rapid and effective clean-up has been obtained with satisfactory recovery values and a negligible matrix effect. The LOQs ranged between 0.020ngmL(-1) for THC-COOH and 0.40ngmL(-1) for OH-THC. The chromatographic conditions obtained with a fused-core column allowed a good separation of the analytes in 6min only. The whole procedure has been validated according to SOFT/AAFS guidelines.

Development and validation of two multiresidue liquid chromatography tandem mass spectrometry methods based on a versatile extraction procedure for isolating non-steroidal anti-inflammatory drugs from bovine milk and muscle tissue.

The main difficulties in analysing non-steroidal anti-inflammatory drugs (NSAIDs) in food and biological samples are due to the tight non-covalent interactions established with matrix proteins and the amount of occurring fatty material. The present paper describes an effective extraction procedure able to isolate fifteen NSAIDs (acetaminophen, salicylic acid, ibuprofen, diclofenac, flunixin and its metabolite 5-hydroxy-flunixin, nimesulide, phenylbutazone, meclofenamic acid, tolfenamic acid, meloxicam, carprofen, ketoprofen, naproxen and etodolac) from bovine milk and muscle tissue through two succeeding steps: (a) deproteinisation/extraction with organic solvent, essential to lower the medium dielectric constant and, therefore, to release the analytes from matrix; (b) SPE clean-up on OASIS cartridges. Lipids were easily removed during low-temperature centrifugations. The advantages of the developed procedure pertain to the efficient removal of the fat substances (very low matrix effect and high recovery yields) and its versatility, since it can be applied both to milk and muscle with few adjustments due to the diversity of the two matrices. Ion-pairing reversed-phase chromatography combined with the negative electrospray detection was able to achieve low detection capabilities (CCßs) for all analytes and, in particular, for diclofenac whose Maximum Residue Limit (MRL) in milk is 0.1 µg kg(-1). The methods were validated according to the guidelines of the Commission Decision 2002/657/EC and then applied for a small monitoring study. A number of samples showed traces of salicylic acid (SA), but its occurrence was not ascribed to a misuse of drugs (aspirin, salicylic acid) since SA, accumulating in plants in response to a pathogen attack, may be introduced into the food chain.