Mario Vincenzo Russo

Rapid analysis of six phthalate esters in wine by ultrasound-vortex-assisted dispersive liquid-liquid micro-extraction coupled with gas chromatography-flame ionization detector or gas chromatography-ion trap mass spectrometry.

An Ultrasound-Vortex-Assisted Dispersive Liquid-Liquid Micro-Extraction (USVADLLME) procedure coupled with Gas Chromatography-Flame Ionization Detector (GC-FID) or Gas Chromatography-Ion Trap Mass Spectrometry (GC-IT/MS) is proposed for rapid analysis of six phthalate esters in hydroalcoholic beverages (alcohol by volume, alc vol(-1), ≤40%). Under optimal conditions, the enrichment factor of the six analytes ranges from 220- to 300-fold and the recovery from 85% to 100.5%. The limit of detection (LOD) and limit of quantification (LOQ) are ≥0.022 μg L(-1) and ≥0.075 μg L(-1), respectively. Intra-day and inter-day precisions expressed as relative standard deviation (RSD), are ≤8.2% and ≤7.0%, respectively. The whole proposed methodology has demonstrated to be simple, reproducible and sensible for the determination of trace phthalate esters in red and white wine samples.

Determination of organophosphorus pesticide residues in human tissues by capillary gas chromatography–negative chemical ionization mass spectrometry analysis

We describe an analytical method that allows the determination of organophosphorus pesticides (OPs) in different human tissues. It involves an extraction procedure with ethanol-ethyl acetate, followed by gel permeation chromatography clean-up step and analysis by capillary gas chromatography-negative chemical ionization mass spectrometry in the selected ion monitoring mode. The method was tested for 37 OPs and the recoveries obtained vary between 60 and 106% with standard deviations ranging between +/-2 and +/-10. These values are independent of the analyzed tissue. Peak area repeatability as RSD for some OPs was < or =4.8% while a good linear relationship in the range 1.0-500 pg microl(-1) with r(2)> or =0.9878 was obtained. The limit of detection for the 37 OPs falls between 0.01 and 0.09 ng g(-1) with an RSD< or =9.5%. The analytical set up in this paper has been used to analyze different samples of human tissues (liver, healthy kidney, cancer kidney and adipose tissue) of 24 patients. The number of the identified OPs in the tissue samples is different (max. 20) according to the sample while their concentration ranges between the limit of detection and 28.0 ng g(-1). The highest concentrations have been determined in liver samples without any pathology (0.4-28.0 ng g(-1)) while the lowest concentrations have been determined in healthy kidney samples (0.01-1.50 ng g(-1)). In the cancer kidney samples OP concentrations vary between 0.03 and 4.6 ng g(-1): these concentrations are more elevated than those determined in healthy kidney samples. The comparison between the concentration of OPs determined in the healthy part, when possible, and those determined in the cancer part of the same kidney sample are very interesting: in fact, in the latter the OP concentration is generally 1-2-times higher than that in the former, an index of lower enzymatic activity in the cancer tissue.

Study of XAD-2 adsorbent for the enrichment of trace levels of phthalate esters in hydroalcoholic food beverages and analysis by gas chromatography coupled with flame ionization and ion-trap mass spectrometry detectors

An analytical method based on solid-phase extraction (SPE) with Amberlite XAD-2 adsorbent used as stationary phase for determining phthalate esters (PAEs) in hydroalcoholic food beverages by GC-FID (and peak confirmation by GC-IT/MS) has been set up. The XAD-2 resin shows excellent properties for determining PAEs in solutions at very large alcoholic range (10-40% v/v): 500mL of hydroalcoholic solution spiked with a PAE mixture solution (20pgμL(-1) of each PAE) and containing 25gL(-1) of NaCl are passed onto a cartridge containing 500mg XAD-2 adsorbent and re-extracted for GC analysis. The effects of NaCl concentration (0, 12, 25 and 50gL(-1)) and different solvents (CS2, toluene, acetone, n-hexane, ethyl acetate) are extensively studied as well the PAE recoveries both in hydroalcoholic aqueous solutions (ranging between 94% and 103% with a Relative Standard Deviation, RSD, below 8.3) and spiked (5, 10 and 25pgμL(-1) of each PAE) real samples (between 90% and 106% with a RSD below 9.9). The correlation coefficients (R(2)) of each PAE vary between 0.9830 and 0.9950 and they are calculated in the linear range 5-100pgμL(-1). The limits of detection (LOD) in GC-FID vary between 1.21 and 2.51pgμL(-1) (RSD⩽11.1) whereas the Limits of Quantification (LOQ) range between 2.42 and 5.03pgμL(-1) (RSD⩽8.9) whereas the infra-day and inter-day repeatabilities calculated as RSD for hydroalcoholic solutions, are between 6.5% and 13.7%.

Ultrasound-vortex-assisted dispersive liquid–liquid microextraction coupled with gas chromatography with a nitrogen–phosphorus detector for simultaneous and rapid determination of organophosphorus pesticides and triazines in wine

A low solvent consumption method for the sensitive determination of organophosphorus (OP) and triazine (TR) pesticides in wine samples is studied. The pesticides were extracted by ultrasound vortex assisted dispersive liquid–liquid microextraction (USVADLLME): 10 mL of sample, 1 mL of NaH2PO4 1 M, 10 μL tolidin in ethanol (internal standard) and 250 μL of C2H4Cl2 (extraction solvent) were vortexed for 30 s (any dispersive solvent was used) and the solution was kept in an ultrasound bath: the extraction was performed at 40 kHz of ultrasound frequency and 110 W for 10 min at room temperature. The determination was performed by means of gas chromatography equipped with nitrogen–phosphorus detector (GC-NPD). The enrichment factors of the analytes ranged from 210 to 232 fold and the recovery ranged from 92.0% to 103.4% (with a Relative Standard Deviation, RSD, below 7.5%). After centrifugation, the bottom phase of the chlorinated solvent was separated from the liquid hydro-alcoholic matrix, dried with anhydrous Na2SO4 and injected into the GC-NPD system. The efficiency of the liquid-phase micro-extraction process was slightly affected by the characteristics of wine samples, therefore the analytical characteristics of the method were evaluated in the linear range 0.01–10 ng mL−1. The correlation coefficients (R2) of each pesticide are above 0.963. The Limits of Detection (LOD) in GC-NPD vary between 0.007 ng mL−1 and 0.07 ng mL−1 (RSD ≤ 9.0) whereas the Limits of Quantification (LOQ) range between 0.024 ng mL−1 and 0.225 ng mL−1 (RSD ≤ 6.9); the intra-day and inter-day repeatabilities, calculated as RSD in the real matrix, are below 6.7% and 8.8%, respectively. Particular attention was devoted to comparing this methodology with other similar analytical methodologies: LODs and RSDs were studied and commented upon. It should be underlined that the good sensibility and high versatility of this methodology allow investigation of organophosphorus and triazine pesticides. At the end, the applicability of the method was demonstrated using commercial wine samples.

Extraction and GC-MS analysis of phthalate esters in food matrices: a review

According to the Scopus database, using “phthalate” and “GC” as keywords, 758 papers have been found between 1990 and 2014, showing strong and increasing interest in this class of compounds from the scientific community. This review focuses attention on phthalate ester (PAE) extraction procedures, followed by GC-MS analysis, applied to food matrices and developed during the last 15 years (from 2000). In this area, 120 papers have been published, divided according to different sample preparation/extraction methods: liquid–liquid extraction (LLE), solid-phase (micro) extraction (SP(M)E), dispersive liquid–liquid (micro) extraction (DLL(M)E), headspace solid-phase micro-extraction (HS-SPME), microwave extraction, supercritical fluid extraction, ultrasonication extraction, thermal desorption extraction and Soxhlet extraction. Finally, for in-depth information, two important issues, phthalate toxicology and risk assessment and the blank problem in analytical determinations, are discussed.

Rapid and simple determination of acrylamide in conventional cereal-based foods and potato chips through conversion to 3-[bis(trifluoroethanoyl)amino]-3-oxopropyl trifluoroacetate by gas chromatography coupled with electron capture and ion trap mass spectrometry detectors.

A new, simple, rapid and fully validated method based on gas chromatography coupled with Electron capture and ion trap mass spectrometry detectors (GC-ECD and GC-IT/MS) is presented for quantitative analysis of acrylamide contaminant in conventional cereal-based foods and potato chips. Before analysis acrylamide was efficiently derivatized with trifluoroacetic anhydride, the effects of temperature, reaction time and catalyst on the acylation reaction were evaluated. Chromatographic analysis was performed on SE-54 capillary column; good retention and peak response of the acrylamide derivative achieved under the optimal conditions. The analytical method has been fully validated by assessment of the following parameters: LODs and LOQs (1 and 25ngg(-1) by GC-ECD and 2 and 36ngg(-1) by GC-IT/MS, with a Relative Standard Deviations <4 and <6, respectively), linearity (R(2) above 0.981 in the range 0.005-50μgg(-1)) and extraction recovery (ranging between 91% and 99%, RSD below 4.0, for acrylamide spiked at levels of 1, 20, 50 and 100ngg(-1)). Furthermore, the method proposed requires no clean-up step of the acrylamide derivative to be performed prior to injection. The developed method has been successfully applied to determine acrylamide in different commercial cereal-based foods (including French fries and potato chips).

Determination of phthalate esters at trace levels in light alcoholic drinks and soft drinks by XAD-2 adsorbent and gas chromatography coupled with ion trap-mass spectrometry detection

An analytical method based on solid phase extraction (SPE) with XAD-2 for the enrichment of seven phthalate esters in light alcoholic drinks (alcohol content below 6% alc vol−1) and in soft drinks has been developed using gas chromatography coupled with an ion-trap mass spectrometer detector (GC/IT-MS). The instrumental analytical protocol was found to yield a linear calibration in the range of 1–800 ng mL−1 with r2 values ≥ 0.912; the limits of detection (LOD) vary between 0.2 pg μL−1 and 20 pg μL−1, whereas the limits of quantification (LOQ) range between 0.6 pg μL−1 and 41 pg μL−1 with relative standard deviations (RSDs) of ≤4.8 and ≤5.5, respectively. The interday precision ranges between 3.6 and 6.3%, whereas the intraday accuracy is between 7.9 and 12.4%. This simple, reliable, reproducible and low-cost analytical method has been applied to several commercial light alcoholic samples such as beers and soft drinks. DEP (0.1–1.0 ng mL−1), DiBP (0.2–2.5 ng mL−1), DBP (1.9–4.4 ng mL−1), BBP (0.08–0.8 ng mL−1), DEHP (3.6–101 ng mL−1) are present in every sample analyzed, whereas DMP (1.9 ng mL−1) and iBcEP (0.08 ng mL−1) are found only in one sample of beer.

Visible light caffeic acid degradation by carbon-doped titanium dioxide

The removal of the phenolic compound, caffeic acid, by photodegradation has been investigated using carbon-doped titanium dioxide particles as a photocatalyst under visible light. UV-vis absorption spectroscopy and gas chromatography-ion trap mass spectrometry analyses revealed a substrate concentration dependence of the removal of caffeic acid from a water solution. The k2 and t(0.5) parameters of each reaction were calculated by fitting kinetics data to a second-order kinetic adsorption model. To evaluate the photodegradation event, the effect of the adsorption process on the whole degradation was also monitored in the absence of light. Adsorption isotherm studies supported by ζ potential and scanning electron microscopy data demonstrated the pivotal role of the absorption mechanism. It was found that the whole photodegradation process is governed by a synergic mechanism in which adsorption and photodegradation are involved. This study, centered on the removal of caffeic acid from aqueous solutions, highlights the potential application of this technology for the elimination of phenolic compounds from olive mill wastewater, a fundamental goal in both the agronomical and environmental fields.

Surface-sampling and analysis of TATP by swabbing and gas chromatography/mass spectrometry

The method of sample recovery for trace detection and identification of explosives plays a critical role in several criminal investigations. After bombing, there can be difficulties in sending big objects to a laboratory for analysis. Traces can also be searched for on large surfaces, on hands of suspects or on surfaces where the explosive was placed during preparatory phases (e.g. places where an IED was assembled, vehicles used for transportation, etc.). In this work, triacetone triperoxide (TATP) was synthesized from commercial precursors following reported methods. Several portions of about 6mg of TATP were then spread on different surfaces (e.g. floors, tables, etc.) or used in handling tests. Three different swabbing systems were used: a commercial swab, pre-wetted with propan-2-ol (isopropanol) and water (7:3), dry paper swabs, and cotton swabs wetted with propan-2-ol. Paper and commercial swabs were also used to sample a metal plate, where a small charge of about 4g of TATP was detonated. Swabs were sealed in small glass jars with screw caps and Parafilm(®) M and sent to the laboratory for analysis. Swabs were extracted and analysed several weeks later by gas chromatography/mass spectrometry. All the three systems gave positive results, but wetted swabs collected higher amounts of TATP. The developed procedure showed its suitability for use in real cases, allowing TATP detection in several simulations, including a situation in which people wash their hands after handling the explosive.

Fast Solid Phase Extraction of Polychlorobiphenyls and Chlorinated Pesticide Residues from Mussels Using Sep-Pak Cartridges

SummaryA rapid method for the determination of chlorinated pesticides and polychlorinated biphenyls in mussels (Mytilus sp.) is reported. The mussel sample is homogenized and extracted with acetonitrile. The organic solution is concentrated and successively diluted with distilled water solution (12 g L−1 NaCl). The organic compounds from water solution are adsorbed onto a NH2 Sep-Pak cartridge.The clean-up step, in which the polychlorobiphenyls and chiorinated pesticides are separated in different eluates, is achieved by passing 25 mL of a 40% methanol aqueous solution through the NH2 Sep-Pak and the C18 Sep-Pak cartridges connected in series.The polychloroblphenyls are desorbed from the NH2 Sep-Pak cartridge whilst the chlorinated peslicides are recovered from the C18 Sep-Pak cartridge.In the separation of polychlorobiphenyls from the chlorinated pesticides tested in this work, only aldrin, hepatachlor and 4,4′-DDD are partially adsorbed with the polychlorobiphenyls onto the NH2 Sep-Pak cartridge.The average recovery is ≥95.0% with a relative standard deviation ≤5.0%. The limits of detection for different pesticides and polychlorobiphenyl congeners are 0.01 and 0.008 μg Kg−1. The final determination is carried out by capillary gas chromatography with ECD.