Roberta Curini

Multiclass analysis of illicit drugs in plasma and oral fluids by LC-MS/MS

AbstractAn analytical procedure for the simultaneous determination in human plasma and oral fluids of several illicit drugs belonging to different chemical and toxicological classes is presented. Amphetamine, methamphetamine, morphine, 6-monoacetylmorphine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethamphetamine, cocaine, benzoylecgonine, tetrahydrocannabinol, carboxytetrahydrocannabinol, ketamine, and phencyclidine have been quantified in real samples using a very rapid sample treatment, basically a protein precipitation. The quantitative analysis was performed by liquid chromatography–tandem mass spectrometry and has been fully validated. All the analytes were detected in positive ionization mode using a TurboIonSpray source, except carboxytetrahydrocannabinol, which was detected in negative ionization mode. The use of a diverter valve between the column and the mass spectrometer allows the preservation of the ion source performances for high-throughput analysis. FigureDiverter system

Analysis of Free Estrogens and their Conjugates in Sewage and River Waters by Solid-Phase Extraction then Liquid Chromatography-Electrospray-Tandem Mass Spectrometry

Summary‘Free’ steroidal estrogens have been identified as compounds possibly responsible for endocrine-disruption of aquatic fauna populating rivers in which municipal sewage-treatment plants (STP) discharge their effluents. Natural and synthetic estrogens are excreted, as glucuronides and sulfates, by man, in the urine but these are bioconverted back to the unconjugated forms in wastewater discharges. For this reason we have developed a sensitive analytical procedure, without derivatization, for identification and quantitation of conjugated and free estrogens in surface and waste waters. The hormones were extracted and fractionated, by use of Carbograph cartridges, into neutral and acid fractions which were then analyzed by liquid chromatography-tandem mass spectrometry. Recoveries were between 66 and 100% and limits of detection (LOD) between 15.0 and 0.003 ng L−1, depending on the compound and the water matrix. When this methodology was applied to real sewage and river water we could measure the main free estrogens at ng L−1 levels. Among the conjugates we always observed the presence of estrone 3-sulfate (at levels between 8.0 and 0.5 ng L−1).

Applications of evolved gas analysis. Part 2: EGA by mass spectrometry

The analytical applications of the evolved gas analysis (EGA) performed by mass spectrometry, for the period extending from 2001 to 2004, are collected in this review. By this technique, the nature of volatile products released by a substance subjected to a controlled temperature program is on-line determined, with the possibility to prove a supposed reaction, either under isothermal or under heating conditions.

Solid-phase extraction followed by high-performance liquid chromatography-ionspray interface-mass spectrometry for monitoring of herbicides in environmental water.

In this work we developed a sensitive and specific multiresidue method, based on reversed-phase liquid chromatography-mass spectrometry, with an ionspray interface (LC-ISI-MS), for determining 52 of most representative compounds of herbicides in water samples. The procedure used involved passing 0.5 l of surface water, 2 l of ground water and 4 l of drinking water samples, respectively, through a 0.5 g graphitized carbon black (GCB) extraction cartridge. Base-neutral and acid herbicides were differential eluted from GCB cartridge and follow analyzed by HPLC-ISI-MS apparatus. A conventional 4.6-mm-ID reversed-phase LC C18 column, operating with a mobile phase flow-rate of 1 ml/min, was used to chromatograph the analytes. A flow of 100 microl/min of the column effluent was diverted to the ISI source. The study demonstrates the sensitivity of the technique, with detection limit under 10 ng/l in drinking water samples. Performance data for the method such as recovery and precision are also reported.

Micro-solid phase extraction coupled with high-performance liquid chromatography-tandem mass spectrometry for the determination of stimulants, hallucinogens, ketamine and phencyclidine in oral fluids.

A confirmatory method for the determination of illicit drugs based on micro-solid phase extraction with modified tips, made of a functionalized fiberglass with apolar chains of octadecylsilane into monolithic structure, has been developed in this study. Drugs belonging to different chemical classes, such as amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, mescaline, phencyclidine and psilocybine were analyzed. The quantitation was performed by liquid chromatography-tandem mass spectrometry and the analytes were detected in positive ionization by means of an electrospray source. The limits of quantification ranged between 0.3 ng mL(-1) for cocaine and 4.9 ng mL(-1) for psilocybine, with coefficients of determination (r(2)) >0.99 for all the analytes as recommended in the guidelines of Society of Forensic Toxicologists-American Association Forensic Sciences.

Comprehensive profiling of carotenoids and fat-soluble vitamins in milk from different animal species by LC-DAD-MS/MS hyphenation.

This paper describes a novel and efficient analytical method to define the profile of fat-soluble micronutrients in milk from different animal species. Overnight cold saponification was optimized as a simultaneous extraction procedure. Analytes were separated by nonaqueous reversed-phase (NARP) chromatography: carotenoids on a C(30) column and fat-soluble vitamins on a tandem C(18) column system. Besides 12 target analytes for which standards are available (all-trans-lutein, all-trans-zeaxanthin, all-trans-β-cryptoxanthin, all-trans-β-carotene, all-trans-retinol, α-tocopherol, γ-tocopherol, δ-tocopherol, ergocalciferol, cholecalciferol, phylloquinone, and menaquinone-4), the DAD-MS combined detection allowed the provisional identification of other carotenoids on the basis of the expected retention times, the absorbance spectra, and the mass spectrometric data. Retinol and α-tocopherol were the most abundant fat-soluble micronutrients and the only ones found in donkeys milk along with γ-tocopherol. Ewes milk also proved to be a good source of vitamin K vitamers. Bovine milk showed a large variety of carotenoids that were absent in milk samples from other species with the only exception of all-trans-lutein and all-trans-zeaxanthin.

Comparison of extracting solutions for elemental fractionation in airborne particulate matter.

It is here described the comparison of extraction efficiency of some solutions (acetate buffer, deionized water, diluted HNO(3) and EDTA) frequently adopted in literature for evaluating the elemental solubility in airborne particulate matter. This comparison was performed considering the distribution of As, Ba, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, S, Si, Sb, Sn, Sr, Ti, V, Zn between the extractable and mineralized residual fractions on the NIST 1648 certified material, PM(10) real samples and size-segregated samples, collected by a 13-stage impactor. The extracting solutions were evaluated by comparing extractive efficiencies and robustness towards some factors, such as acidity and concentration of complexing species, that have great environmental variability and that could be able to modify the extractive efficiency. Furthermore, extraction methods application to size-segregated samples allowed estimating the selectivity of extracting solutions towards dimensionally characterized emission sources, as dusts originated from abrasion and road dust re-suspension. On the basis of the obtained results, it was possible to define the main advantages and disadvantages resulting from the use of different extracting solutions, necessary to make possible the comparison of environmental studies carried out in different extractive conditions and to start up a proper study for harmonizing extracting procedures.

Amino acid profile in the ripening of Grana Padano cheese : a NMR study

Among typical Italian cheeses, Grana Padano is the most famous, with the biggest production. The final step in the cheesemaking is the natural ripening, which involves many modifications of high complexity. In the present work, thermoanalytical and spectroscopic techniques are applied to Grana Padano cheese as a new analytical approach. These are thermogravimetry (TG) and derived thermogravimetry (DTG) to determine different types of water present in the cheese matrix, low-resolution nuclear magnetic resonance (NMR) to provide information on the water localization and displacements within the foodstuff and high-resolution nuclear magnetic resonance (NMR) to evaluate all the amino acids present in the cheese. Modifications in both water and free amino acid contents are observed, as a function of the ripening time and of the distance from the centre of the cheese wheel.

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 a rapid assay based on liquid chromatography–tandem mass spectromtetry for determining macrolide antibiotic residues in eggs

A simple and rapid method able to determine residues of erythromycin A, tylosin and tilmicosin in whole eggs is presented here. The analytical protocol involves a one-step extraction followed by liquid chromatography (LC)-tandem mass spectrometry. Analytes were extracted from 1g of egg spiked with an internal standard (josamycin) with acetonitrile. In terms of accuracy, matrix effect and ion signal stability, no extract cleanup was found to be necessary. After partial solvent removal, the final extract was injected into the LC column. Extraction was effective, since absolute recovery of the analyte in egg at their maximum residue limit (MRL) level was 85-102%. Estimated limits of quantification (S/N=10) were 0.2-0.5 ng/g. Based on the EU Commission Decision 2002/657/EC, the method was in-house validated in terms of ruggedness, specificity, linearity, within-laboratory reproducibility, decision limit (CCalpha) and detection capability (CCbeta). The within-laboratory reproducibility, expressed as RSD (n=18 at the MRL levels), was not higher than 13%. After validation, a short study on EA depletion in eggs was conducted after administration of this drug to laying hens.