Giuseppe Cinelli

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.

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.

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.

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.

The role of microemulsions in lipase-catalyzed hydrolysis reactions

The kinetics of the p‐nitrophenyl butyrate hydrolysis reaction, catalyzed by Candida rugosa lipase in the water‐in‐oil microemulsion cetyltrimethylammonium bromide/water/pentanol/hexane, was investigated. The results described in the present manuscript reveal two peculiar characteristics of the reaction: (i) the initial rate of hydrolysis is very fast and (ii) by decreasing the water content of the microemulsion, the reaction rate approaches the typical behavior of reactions performed in aqueous solution. In particular, for microemulsion systems with a high water content, the end points of the reactions are dictated by the shape stability of the microemulsion. For these systems, our methodological approach shows that the process follows a second‐order kinetics equation, indicative of the dual role played by water, which is involved both as a component of the microemulsion, i.e., relevant for the microemulsion stability and as a reagent of the hydrolysis reaction. In contrast, for microemulsions containing a small amount of water, after the hydrolysis reaction the system seems to fall in the no existence range of the microemulsion. Accordingly, the kinetics results are more complex: in the initial stage, the reaction follows a zero‐order kinetics equation, while for longer reaction times a first‐order kinetics equation fits the experimental data, as would be expected for an enzymatic reaction in a homogeneous system.

Use of Rhodotorula minuta Live Cells Hosted in Water‐in‐Oil Macroemulsion for Biotrasformation Reaction

A lecithin/water/isooctane water‐in‐oil (w/o) macroemulsion was used as a host system for biotransformation reactions. In particular, the hydrolytic activity of the yeast Rhodotorula minuta toward (±)‐succinic acid bis‐2‐isopropyl‐5‐methylcyclohexyl ester and p‐nitrophenyl butyrate is reported. Evidence that R. minuta entrapped in w/o macroemulsion is able to hydrolyze the p‐nitrophenyl butyrate ester is presented. By performing the yeast‐catalyzed hydrolysis of (±)‐succinic acid bis‐2‐isopropyl‐5‐methylcyclohexyl ester, the synthesis of (–)‐menthol was obtained, indicating that R. minuta retains its high stereoselectivity in the macroemulsion system. In addition, no significant differences were observed among the hydrolysis rates and yields obtained using yeast cells hosted into w/o macroemulsions containing different amounts of water. Optical microscopy studies on the distribution of diameters of the dispersed phase indicate that the macroemulsion system is stable in terms of polydispersity. The diameter of the w/o macroemulsion droplets is indeed constant irrespective of the addition of water and/or chemicals (involved in the biotransformation reaction) to the system hosting yeast cells. The reactor devised here might be applied to other interesting bioconversion processes.

Trace determination of acaricides in honey samples using XAD-2 adsorbent and gas chromatography coupled with an ion trap mass spectrometer detector

Various infectious/parasitic diseases affect beekeeping (e.g., Varroa destructor) and substances like acaricides are largely used as pesticides to tackle this problem, in particular tau-fluvalinate, fipronil, bromopropylate, amitraz, and coumaphos. A key issue in their use though is potential ingress into the human food chain, and in this regard accurate residue determination of such compounds in honey foods at trace concentration levels is critical. This paper describes an analytical methodology for determining qualitatively and quantitatively the acaricide residues in such foods. A solid-phase extraction method has been developed for the extraction and analysis of five acaricides in honey-foods using XAD-2 sorbent. Gas Chromatography coupled with an Ion Trap Mass Spectrometer detector (GC-IT/MS) was used for the analysis. The isotherm and breakthrough curves for XAD-2 solution are reported here. The developed procedure allows efficient acaricide recoveries, ranging from 81–96% with relative standard deviations (RSDs) of ≤6.9 for honey-food samples. The linearity (R2) of each acaricide has been investigated in the range 0.030–10.0 μg g−1 for evaluating the whole analytical protocol, R2 values are ≥0.945. The intraday and interday repeatabilities for honey samples were between 4.1–9.2 and 2.4–5.6, respectively. Special note has been made to the determination of the Limits of Detection (LODs) and the Limits of Quantification (LOQs) and their relative comparison with those reported in literature and those in International regulations: for GC/IT-MS (SIM mode), LODs vary between 3 ng g−1 and 18 ng g−1 (RSD ≤ 4.9), whereas LOQs range between 8 ng g−1 and 48 ng g−1 (RSD ≤ 8.3). The analytical method developed here has been applied to several commercial honey-foods (Millefiori, molasses, royal jelly). The investigated method is simple, selective, reproducible, reliable, and inexpensive.

Olive Mill Wastewater (OMW) Phenol Compounds Degradation by Means of a Visible Light Activated Titanium Dioxide-Based Photocatalyst

Abstract The use of titanium dioxide as heterogeneous photocatalyst is drawing considerable attention for water and air purification and remediation. Recently, TiO2 particles have been modified in order to make this material attractive for industrial and environmental remediation usage. In the present study, phenolic compounds of olive mill wastewater (OMW) were degraded in the presence of glucose-doped titanium particles (CDT) through a photocatalysis process activated by visible light. The photocatalyst effectiveness towards the polluted wastewater from olive oil industry was tested on systems having different initial concentrations of phenols and in the presence of different amounts of CDT. For kinetic analysis the role of Ti/TPh ratio (amount of catalyst/amount of total phenols) was investigated. The rate constant (k2) and the amounts of species adsorbed on adsorbent at equilibrium (qe) of each reaction were calculated by fitting kinetics data to a second-order kinetic adsorption model. The results collected at different Ti/TPh ratios showed that the amount of phenols that can be removed from the water solution linearly increases with the Ti/TPh ratio till a maximum value (optimal ratio) at which no further degradation of phenolic compounds was obtainable. Such kind of parameter allows to identify the optimal value of catalyst and the initial substrate concentration for a high level of degradation. The results showed in this study can have an important impact for an applicative point of view.