Giuseppe D’Ascenzo

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

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.

Simple assay for monitoring seven quinolone antibacterials in eggs: extraction with hot water and liquid chromatography coupled to tandem mass spectrometry: laboratory validation in line with the European Union Commission Decision 657/2002/EC.

A simple and rapid method able to determine residues of seven quinolone antibacterials in whole eggs is presented here. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography-tandem mass spectrometry. After depositing 1.5 g of an egg sample containing the analytes and the analyte surrogate (norfloxacin) on sand (crystobalite), this material was packed into an extraction cell. Quinolones were extracted by flowing 6 mL of water acidified with 50 mmol/L formic acid through the cell heated at 100 degrees C. After pH adjustment and filtration of the extract, 100 microL of it was injected into the LC column. MS data acquisition was performed in the multiple reaction monitoring mode, selecting two precursor ion to product ion transitions for each target compound. Hot water appeared an efficient extracting medium, since absolute recoveries of the analyte in egg at the level of 20 ng/g were 89-103%. Estimated limits of quantification (S/N=10) were 0.2-0.6 ng/g. Based on the EU Commission Decision 2002/657/EC, the method was validated in terms of ruggedness, specificity, linearity, within-laboratory reproducibility, decision limit (CCalpha and detection capability (CCbeta). Depending on the particular analyte, CCalphas ranged between 0.41 and 2.6 ng/g, while CCbetas were 0.64-3.7 ng/g. The method was linear in the 3-30 ng/g range, with typical R(2) values higher than 0.97. The within-laboratory reproducibility (n=21) at 6 ng/g level was in the 9.0-12% range. After validation, a depletion study of enrofloxacin and one of its metabolites, i.e. ciprofloxacin, in eggs was conducted.

Neutral loss and precursor ion scan tandem mass spectrometry for study of activated benzopyrene–DNA adducts

AbstractMethodology for detection of activated benzo[a]pyrene (B[a]P)–nucleoside adducts by liquid chromatography–tandem mass spectrometry is reported. Adducts of B[a]P-dihydrodiol epoxide (B[a]PDE) with guanosine and adenosine have been detected for the first time by use of precursor ion scan and neutral loss scan. B[a]P was then activated by use of UV irradiation and some of the products obtained have been identified by taking advantage of the information obtained for B[a]PDE. Photoactivation has also been carried out in the presence of hydrogen peroxide; this resulted in a higher yield of products with increased production of BaP diones. The reactivity of these compounds toward nucleosides has been tested. The proposed method was successfully used for detection of one stable guanosine–B[a]P dione adduct. FigureInteractions between activated B[a]P and DNA; MS/MS detection strategies

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.

Determination of Illicit Drugs in Urine and Plasma by Micro-SPE Followed by HPLC–MS/MS

Confirmation of identity of forensically relevant compounds, such as drugs of abuse, is a necessary step in medico-legal event controls of people involved in crimes, workplace accidents and driving under the influence of drugs (DUID). Plasma is a useful medium in determining the short-term use of illicit drugs and its analysis is mandatory in the case of DUID in many countries. Urine has been the sample of choice for monitoring drug abuses in workplaces and is subjective to strict regulations. The aim of this work was the development of a fast and reliable confirmatory method for the determination of multiple drugs of abuse belonging to different chemical and toxicological classes: amphetamine, methamphetamine, methylenedioxyamphetamine, methylenedioxyethylamphetamine, methylenedioxymethylamphetamine, cocaine, benzoylecgonine, ketamine, phencyclidine, psilocybin and mescaline. The procedure involves very rapid steps of sample preparation with use of automated micro-SPE. The quantitative analysis is performed by LC–ESI-MS/MS with chromatographic Core Shell™ column. The method has been fully validated according to SOFT-AAFS guidelines and applied as confirmatory analysis for real samples coming from agro-industry employees.

Study of on-line analysis using energy dispersive X-ray fluorescence spectrometry for controlling lanthanum and neodymium extraction

Abstract Many rare-earth extraction processes require frequent control over separation process quality. Ideally, an analysis method for this type should be simple, rapid and reliable. Energy dispersive X-ray fluorescence (EDXRF) spectrometry, due to its relative simplicity of instrumentation, speed of analysis, and non-destructive nature, is well suited to this on-line analysis application. In particular, since the radioisotope energy dispersive XRF method eliminates the need to transport samples to a laboratory which houses the X-ray spectrometry, it is most commonly used for on-line analysis of extraction systems. The present paper describes an attempt to type the radioisotope source 241 Am XRF on-line analysis arrangement coupled with a personal computer for controlling a lanthanum and neodymium separation process. From the HpGe detector response, a continuous spectral signal is observed during loading of the feed samples. The separation process using countercurrent extraction consists of a 16-stage laboratory mixer-settler, a switching valve, and a pumping system. The performance of this control system is illustrated by extracting La, Nd acidic solutions with 100% tributyl phosphate.

Simulation of the development automatization control system for rare earth extraction process: Combination of ESRECE simulation software and EDXRF analysis technique

Abstract Recently, the requirement of developing the automatic control for rare earth extraction processes has been attracting a lot of attention. However, due to the similarity of chemical physical properties of rare earth, the separation of these elements requires a great number of stages of mixer-settles. The multistage countercurrent extraction system, consisted of two immiscible flowing phases—the organic phase and the aqueous phase and the variable composition take place stage by stage. This plant generally requires a continuous control the status of the separation process and its efficacy, in order to prevent appearing an ‘out-of-specification product’ or a high raffinate value. For studying the steady or dynamic performance of stage-wise processes, and establishing the relative controlling system, the on-line EDXRF analytical technique and ESRECE simulation system were used in our laboratory.