Francesc Borrull

Determination of personal care products in sewage sludge by pressurized liquid extraction and ultra high performance liquid chromatography-tandem mass spectrometry.

This paper describes a method for the determination of a group of personal care products including four UV filters, four preservatives and two antimicrobials in sewage sludge. The method combines pressurized liquid extraction and ultra high performance liquid chromatography-tandem mass spectrometry. Most of the parameters that affect the extraction step such as temperature, pressure, static extraction time, number of cycles, purge time and flush volume were optimized using a fractional experimental design. In the chromatographic step, the compounds were detected by using tandem mass spectrometry with a triple quadrupole analyzer with electrospray ionization in positive and negative modes. The use of small diameter particles (1.8 microm) in the chromatographic column allowed the compounds to be eluted in 9 min. The entire process took a total of 39 min. All recoveries were higher than 72% except for 2,4-dihydroxybenzophenone (a UV filter), whose recovery was 30%. The repeatability and reproducibility between days expressed as RSD (%) (n=3) were less than 8% and 13%, respectively. The LODs and LOQs were lower than 8 microg/kg and 12.5 microg/kg of dry weight (d.w.), respectively. When the method was applied to determine the compounds in sewage sludge from a domestic sewage treatment plant, triclosan (an antimicrobial) and octocrylene (a UV filter) showed the highest levels, 1490 microg/kg (d.w.) and 1842 microg/kg (d.w.), respectively. This paper describes for the first time the determination of parabens and two UV filters (octyldimethyl-p-aminobenzoic acid and benzophenone-3) in sewage sludge.

Determination of antibiotic compounds in water by solid-phase extraction–high-performance liquid chromatography–(electrospray) mass spectrometry

We developed a sensitive method based on solid-phase extraction and high-performance liquid chromatography coupled to mass spectrometry using an electrospray interface for the determination of four tetracyclines and two quinolones in water. The method was applied to river, well and sewage-treatment-plant waters. For the solid-phase extraction of 1000 ml river water samples, recoveries were between 88 and 112% and limits of detection were as low as 4 and 6 ng l(-1). Recoveries were higher than 64% for 1000 ml well water samples for the majority of the compounds. For the influent and effluent of the sewage-treatment-plant sample volumes of 100 and 250 ml were extracted, respectively. The method developed allowed ciprofloxacin to be determined in samples from the influent and effluent of the sewage-treatment-plant at 0.58 and 0.60 microg l(-1), respectively.

Determination of quinolones in plasma samples by capillary electrophoresis using solid-phase extraction.

The potential of capillary zone electrophoresis (CZE) and micellar electrokinetic capillary chromatography (MEKC) have been investigated for the separation and quantitative determination of 10 quinolone antibiotics. The influence of different conditions, such as the buffer and pH of the electrolyte, the surfactant and the ion-pairing agents added to the electrolyte and the organic modifier were studied. A buffer consisting of 40 mM sodium tetraborate at pH 8.1 containing 10% (v/v) methanol was found to be a highly efficient electrophoretic system for separating lomefloxacin, enoxacin, norfloxacin, pipemidic acid, ofloxacin, piromidic acid, flumequine, oxolinic acid, cinoxacin and nalidixic acid. A solid-phase extraction method to remove the sample matrix (pig plasma samples) was developed on a C(18) cartridge using a mixture of methanol-water (70:30, v/v). The method is specific and reproducible and mean recoveries were in the range 94.0+/-4.2% and 123.3+/-4.1% for pig plasma samples over the range used. A linear relationship between concentration and peak area for each compound in pig plasma samples was obtained in the concentration range 5-20 mg l(-1) and detection limits were between 1.1 and 2.4 mg l(-1).

Risk assessment related to atmospheric polycyclic aromatic hydrocarbons in gas and particle phases near industrial sites.

Background: Inhalation is one of the main means of human exposure to polycyclic aromatic hydrocarbons (PAHs) because of their ubiquitous presence in the atmosphere. However, most studies have considered only PAHs found in the particle phase and have omitted the contribution of the gas-phase PAHs to the risk. Objective: We estimated the lifetime lung cancer risk from PAH exposure by inhalation in people living next to the largest chemical site in Southern Europe and the Mediterranean area. Methods: We determined 18 PAHs in the atmospheric gas and particle phase. We monitored the PAHs for 1 year in three locations near the chemical site in different seasons. We used toxic equivalence factors to calculate benzo[a]pyrene (BaP) equivalents (BaP-eq) for individual PAHs and applied the World Health Organization unit risk (UR) for BaP (UR = 8.7 × 10–5) to estimate lifetime cancer risks due to PAH exposures. Results: We observed some spatial and seasonal variability in PAH concentrations. The contribution of gas-phase PAHs to the total BaP-eq value was between 34% and 86%. The total estimated average lifetime lung cancer risk due to PAH exposure in the study area was 1.2 × 10–4. Conclusions: The estimated risk was higher than values recommended by the World Health Organization and U.S. Environmental Protection Agency but lower than the threshold value of 10–3 that is considered an indication of definite risk according to similar risk studies. The results also showed that risk may be underestimated if the contributions of gas-phase PAHs are not considered.

Determination of ciprofloxacin, enrofloxacin and flumequine in pig plasma samples by capillary isotachophoresis--capillary zone electrophoresis.

Quinolones are a group of synthetic antibiotics that are widely used in veterinary medicine. Their residues may remain in tissues, milk, etc. intended for human consumption. The European Union fixes the maximum residue limits (MRLs) of veterinary medicinal products in foodstuffs of animal origin. Analytical methods are therefore needed to determine them in biological samples. In this study, we describe capillary isotachophoresis-capillary zone electrophoresis (ITP-CZE) to analyze three quinolones, enrofloxacin (ENR), ciprofloxacin (CPR) and flumequine (FLU), in pig plasma samples. We used solid-phase extraction with Oasis HLB cartridges as a sample pretreatment clean-up step. Capillary zone electrophoresis (CZE) requires low amounts of sample and is not as sensitive as one would wish. ITP-CZE is an easy way to increase the sample loadability and sensitivity. With this system sensitivity increases 40-fold. The detection limits for CPR, ENR and FLU were 70, 85 and 50 microg l(-1), respectively, which were lower than their MRLs in different kinds of samples. This method is simple and sensitive, and is therefore an alternative tool to the existing HPLC methods for analyzing the residuals of these quinolones in biological samples.

Chronic risk assessment of exposure to volatile organic compounds in the atmosphere near the largest Mediterranean industrial site

This study focuses on characterising the risk of exposure to volatile organic compounds (VOCs) by means of inhalation in people living in the vicinity of the largest chemical production site in the Mediterranean area. Eighty-six VOCs were initially selected for this study based on their adverse environmental and health effects. The monitoring campaign was conducted for 276 days in three different locations around the chemical site. The analytical method used for the characterisation was based on European standard method EN-14662-2, which consists of the active sampling of air for 24h in charcoal tubes, followed by extraction with carbon disulphide and GC-MS analysis. Forty-four VOCs with toxicological data available concerning their carcinogenic and non-carcinogenic health effects were quantified during the monitoring campaign. None of the quantified VOCs showed average concentrations exceeding their chronic reference concentrations and, therefore, no non-carcinogenic health effects are expected as a result of this exposure. However, the global average cancer risk due to VOC exposure in the area (3.3×10(-4)) was found to be above the values recommended by the WHO and USEPA. The influence of the analytical method was also evaluated by comparing cancer risk estimates using a thermal desorption (TD) method based on method EN-14662-1. The results of the 24-h samples for the solvent extraction method were compared with the average of 12 daily samples of 2-h for the TD method for 24 sampling days. Although the global estimated lifetime cancer risk was statistically comparable for both methods, some differences were found in individual VOC risks. To our knowledge, this is the first study that estimates the carcinogenic and non-carcinogenic risks posed by the inhalation of VOCs in people living near a chemical site of this size, and compares the estimated cancer risk obtained using two different standard analytical methods.

Determination of macrolide antibiotics in meat and fish using pressurized liquid extraction and liquid chromatography–mass spectrometry ☆

We developed a method for determining the quantities of seven macrolide antibiotics in meat and fish by using pressurized liquid extraction (PLE) and liquid chromatography-mass spectrometry with electrospray ionization (LC-(ESI)MS). The PLE was optimized with regard to solvents, temperature, pressure, extraction time and number of cycles. The optimum conditions were: methanol as the extraction solvent; a temperature of 80 degrees C; a pressure of 1500psi; an extraction time of 15min; 2 cycles; a flush volume of 150% and a purge time of 300s. All recoveries for macrolide antibiotics were over 77% at 200mug/kg, except for erythromycin, which was 58%. The repeatability and reproducibility on days in between, expressed as %RSD (n=12), were lower than 10% and 12%, respectively. The quantification limits of all compounds were 25mug/kg of dry weight of animal muscle except for troleandomycin (50mug/kg). The method was applied to determine the pharmaceuticals in real samples taken from 18 meat and fish samples. The results showed that PLE is quantitative short time consuming technique, with use of smaller initial sample sizes. Greater specificity and selectivity in extraction and increased potential for automation were shown.

Determination of biogenic amines in wines by high-performance liquid chromatography with on-column fluorescence derivatization

An on-column fluorometric derivatization method was developed for determining eight biogenic amines by HPLC and fluorometric detection. The derivatization was carried out by pumping the o-phthalaldehyde reagent through the column together with other solvents used as mobile phases. The on-column reaction conditions (pH, borate and o-phthalaldehyde concentrations) were optimized. The matrix effect, the thiol used in the derivative reagent and the effect of the temperature on the separation process were also studied. Solid-phase extraction was applied prior to the derivatization procedure as a clean-up of wines by using 2 different commercially available SAX and C18 cartridges to improve the accuracy and the precision of the method. The linearity range (0.5–15 mg 1−1) and detection limits (between 100 and 300 μg l−1) of this method were similar to the standard pre-column automated o-phthalaldehyde derivatization method. The method was checked with several red wines from Tarragona by comparing the results with the standard pre-column method.

Determination of carboxylic acids, sugars, glycerol and ethanol in wine and grape must by ion-exchange high-performance liquid chromatography with refractive index detection

Method to determine the major carboxylic acids, sugars, glycerol and ethanol in wine and grape must was developed using an ion-exchange column and refractive index detector. A solid-phase extraction method with a strong anion exchanger was used to determine these compounds in sweet wines and in grape musts. With this method it is possible to determine malic acid in sweet wines and in grape musts without interference from sugars. This high-performance liquid chromatographic method was compared with standard methods of analysis. There was good agreement in the accuracy and precision of the compared methods.

Estrogens and their conjugates: determination in water samples by solid-phase extraction and liquid chromatography-tandem mass spectrometry.

A sensitive method for simultaneously determining eleven free and conjugated steroid estrogens has been developed using liquid chromatography-(electrospray)triple quadrupole-mass spectrometry (LC-(ESI)MS-MS) in negative mode with application to environmental aqueous matrices. Two selected reaction monitoring (SRM) transitions per compound were used, one of which was used for quantification and the second one for confirmation. The procedure includes a solid-phase extraction with an Oasis HLB solid-phase cartridge. Recoveries in 500 mL of river water spiked at 50 ng/L for sulfate estrogens and 100 ng/L for the rest of the compounds were 46-87%, except for E2, which had lower values (32%). Recoveries in wastewater were higher than 49% and 30% for all the compounds, except E2-17A and E2-17G (lower than 26% and 28%, respectively), in effluent (250 mL) and influent (100 mL), respectively. Ion suppression is a well-known phenomenon when using ESI; thus its impact on method recovery made us consider this effect when quantifying our samples. Limits of detection varied from 2 to 30 ng/L in river water and 10 to 100 ng/L in sewage water. The method was used to determine the target compounds in the Ebro river water where none of the analytes were found. In effluent and influent water samples, EE2, E1-3S and E2-3S were determined at concentration levels ranging from 35 to 160 ng/L.