Lucia Mainero Rocca

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.

Residue analysis of glucocorticoids in bovine milk by liquid chromatography–tandem mass spectrometry

A sensitive liquid chromatography–tandem mass spectrometry (LC-MS/MS) method for the simultaneous determination of 13 steroidal anti-inflammatory drugs in bovine milk is presented. Due to their weakly acid nature, analytes were separated by ion suppression reversed phase chromatography and detected in positive-ion mode by a high flow electrospray source. Dexamethasone-d4 was used as internal standard. The sample preparation was simple and reliable; it included acidic deproteinization of milk followed by sample enrichment and clean-up, utilizing a C18 solid phase extraction cartridge. Recoveries exceeded 70% with an intra-day precision not larger than 12%. The efficiency of the sample clean-up and internal standardization rendered negligible the matrix effect, estimated by comparing standard and matrix-matched calibration curves. A small-scale reconnaissance was carried out on several raw and whole fresh milk samples. A large number of analyzed samples showed a chromatographic peak, in the retention time window of cortisol, at levels included between its decision limit (CCα) and detection capability (CCβ). As a result of a heat-induced transformation, an isomeric product of triamcinolone was observed during the extract evaporation. Since this rearrangement might occur during the milk pasteurization process, LC-MS/MS and 1H-NMR investigations were performed out to conclusively differentiate the two isomers. One- and two-dimensional proton NMR spectra were able to identify the transformation product as 9a-fluoro-11b,16a-trihydroxy-17b-hydroxymethyl-D-homoandrosta-1,4-diene-3,17a-dione.

DESI-MS2: a rapid and innovative method for trace analysis of six cytostatic drugs in health care setting

AbstractWith the aim of establishing exposure levels for hospital personnel preparing and administering cytostatic drugs (CDs), here, we present an innovative screening method based on the use of the desorption electrospray ionization (DESI) interface coupled with a hybrid quadrupole linear ion trap mass spectrometer. A rapid, simple, and sensitive procedure was developed for the simultaneous surface monitoring of cyclophosphamide, dacarbazine, methotrexate, vincristine, gemcitabine, and cytarabine. Since analytes were in the solid state, a novel approach based on the use of passive samplers was combined with the direct analysis of wipes. A PTFE-printed glass slide was used as a passive sampler, while hydrophobic centers of Swiffer® cloths were judged extremely efficient as wipe samplers. After the sampling period, the CD collectors were directly processed with the DESI-MS system without any further treatment. MS/MS confirmatory analysis was conducted using selected reaction monitoring in the positive ion mode and detection limits were evaluated. Values were at the picograms per square millimeter levels on the passive collector and at the picograms per square centimeter levels for the wipe ones. Direct determination on solid-state samples combined with mass spectrometry selectivity provided a powerful tool so far unapplied to occupational hygiene. FigureDESI interface detail (spray emitter and MS inlet) with 3D spacefill structures of the six cytostatic drugs analyzed

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

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.

Occurrence of non-steroidal anti-inflammatory drugs in surface waters of Central Italy by liquid chromatography–tandem mass spectrometry

Non-steroidal anti-inflammatory drugs (NSAIDs) are considered to be the cure-all of any pain: from headache and cold symptoms to toothaches and even labour pain. Their wide use in human medicine has been favoured by the possibility to purchase them without medical prescription, their low cost and by the absence of opioid-like side effects. At the same time, their administration to domestic and food-producing animals has become a common practice to improve their well-being. Therefore, human and veterinary applications are the main sources of NSAIDs in the environment and the major pathways are excretion and discharge through sewage treatment plants. Although their environmental occurrence is well-known, there is a lack of data regarding their levels in surface waters of Central Italy. In this study, a monitoring campaign was arranged in some of the most important rivers and lakes of Central Italy, characterised by a different anthropic impact, in spring–summer and autumn–winter 2012. A broad range of NSAIDs for human and animal use was analysed through a reliable analytical method based on liquid chromatography–tandem mass spectrometry, appropriately developed and validated. Results have shown the constant presence of all drugs commonly used in human medicine with a composition that mirrored the incidence of seasonal diseases quite well. A veterinary drug (flunixin) was found in Bracciano Lake (Rome district), an important tourist attraction surrounded by farmlands. Salicylic acid is a phytohormone and this explains its presence in all the analyzed samples. All the results collected during the extensive survey have proved that Central Italy is aligned with the rest of Europe since its natural waters have shown low levels of contamination (ng L−1) but with a chronic input.

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

ABSTRACT 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. Graphical Abstract

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

ABSTRACT 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 (CCβ) 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.

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

ABSTRACT 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. Graphical Abstract

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.