J. Pablo Lamas

Simultaneous determination of traces of pyrethroids, organochlorines and other main plant protection agents in agricultural soils by headspace solid-phase microextraction–gas chromatography

A solvent-free and simple method based on headspace solid-phase microextraction (HS-SPME) was developed in order to determine simultaneously 36 common pesticides and breakdown products (mostly pyrethroids and organochlorine compounds) in soil. The analysis was carried out by gas chromatography with micro-electron-capture detection (GC-microECD). As far as we know, this is the first study about the SPME of pyrethroid insecticides from soil. Factors such as extraction temperature, matrix modification by addition of water, salt addition (% NaCl) and fiber coating were considered in the optimization of the HS-SPME. To this end, a 3 x 2(3-1) fractional factorial design was performed. The results showed that temperature and fiber coating were the most significant variables affecting extraction efficiency. A suitable sensitivity for all investigated compounds was achieved at 100 degrees C by extracting soil samples wetted with 0.5 mL of ultrapure water (0% NaCl) employing a polyacrylate (PA) coating fiber. Using the recommended extraction conditions with GC-microECD, a linear calibration could be achieved over a range of two orders of magnitude for both groups of analytes. Limits of detection (LODS) at the sub-ng g(-1) level were attained and relative standard deviations (RSDs) were found to be lower than 14% for both groups of pesticides. Matrix effects were investigated by the analysis of different soil samples fortified with the target compounds. The method accuracy was assessed and good recovery values (>70%, in most cases) were obtained. The method was also validated with a certified reference material (RTC-CRM818-050), which was quantified using a standard addition protocol. Finally, the proposed HS-SPME-GC-microECD methodology was further applied to the screening of environmental soil samples for the presence of the target pesticides.

Development of a solid-phase microextraction gas chromatography with microelectron-capture detection method for a multiresidue analysis of pesticides in bovine milk

A simple and rapid method based on solid-phase microextraction (SPME) technique followed by gas chromatography with microelectron-capture detection (GC-microECD) was developed for the simultaneous determination of more than 30 pesticides (pyrethroids and organochlorinated among others) in milk. To our knowledge, this is the first application of SPME for the determination of pyrethroid pesticides in milk. Negative matrix effects due to the complexity and lipophility of the studied matrix were reduced by diluting the sample with distilled water. A 2(5-1) fractional factorial design was performed to assess the influence of several factors (type of fiber coating, sampling mode, stirring, extraction temperature, and addition of sodium chloride) on the SPME procedure and to determine the optimal extraction conditions. After optimization of all the significant variables and interactions, the recommended procedure was established as follows: DSPME (using a polydimethylsiloxane (PDMS)/divinylbenzene (DVB) coating) of 1 mL of milk sample diluted with Milli-Q water (1:10 dilution ratio), at 100 degrees C, under stirring for 30 min. The proposed method showed good linearity and high sensitivity, with limits of detection (LOD) at the sub-ng mL(-1) level. Within a day and among days precisions were also evaluated (R.S.D.<15%). One of the most important attainments of this work was the use of external calibration with milk-matched standards to quantify the levels of the target analytes. The method was tested with liquid and powdered milk samples with different fat contents covering the whole commercial range. The efficiency of the extraction process was studied at several analyte concentration levels obtaining high recoveries (>80% in most cases) for different types of full-fat milks. The optimized procedure was validated with powdered milk certified reference material, which was quantified using external calibration and standard addition protocols. Finally, the DSPME-GC-microECD methodology was applied to the analysis of milk samples collected in farms of dairy cattle from NW Spain.

Analysis of plasticizers and synthetic musks in cosmetic and personal care products by matrix solid-phase dispersion gas chromatography–mass spectrometry

Matrix solid-phase dispersion (MSPD) and gas chromatography-mass spectrometry were used for the rapid determination of 18 plasticizers (phthalates and adipates), 7 polycyclic musks and 5 nitromusks, which makes a total of 30 targets, in both rinse-off and leave-on cosmetic formulations. The MSPD method was miniaturized and customized to avoid or minimize risks of phthalate contamination and to reduce residues and costs. The amount of sample and extraction solvent employed were 0.1g and 1mL, respectively. The procedure was optimized by means of an experimental design and under the optima conditions it showed satisfactory linearity, repeatability and intermediate precision. LOQs were, in general, in the low ngg(-1), and recoveries were quantitative for all the 18 plasticizers and the 12 fragrances. Twenty-six cosmetic products such as creams, emulsions, lotions, gels for the skin, bath and shower preparations, deodorants, hair-setting, hair-cleansing and hair-conditioning products, shaving products, and sunbathing products, were analyzed. Twenty-five out of thirty targets were detected in the samples. The most frequently found compounds were galaxolide and tonalide reaching concentrations above 0.1% (1000μgg(-1)), and diethyl phthalate (between 0.7 and 357μgg(-1)). The presence of banned substances (Regulation (EC) No. 1223/2009) such as dibutyl phthalate, diisobutyl phthalate, dimethoxyethyl phthalate, benzylbutyl phthalate, diethylhexyl phthalate, diisopentyl phthalate and dipentyl phthalate, musk ambrette and musk tibetene was confirmed in sixteen of the twenty-six personal care products (62%).

Multicomponent analytical methodology to control phthalates, synthetic musks, fragrance allergens and preservatives in perfumes.

A simple, fast, robust and reliable multicomponent analytical method applicable in control laboratories with a high throughput level has been developed to analyze commercial brands of perfumes. Contents of 52 cosmetic ingredients belonging to different chemical families can be determined in a single run. Instrumental linearity, precision of the method and recovery studies in real samples showed excellent results, so that quantification by external calibration can be effectively applied. Relevant limits of detection and quantification were obtained for all the targets considered, far below the legal requirements and amply adequate for its accurate analytical control. A survey of 70 commercial perfumes and colognes has been performed, in order to verify whether these products complied with the recent changes in European legislation: regarding the maxima allowed concentrations of the ingredients and/or ingredient labelling. All samples contained some of the target ingredients. Several samples do not comply with the regulations concerning the presence of phthalates. Musks data confirmed the trend about the replacement of nitromusks by polycyclic musks; as well as the noticeable introduction of macrocyclic musks in the perfumes composition. The prohibited musk moskene has been detected in one sample in an appreciable concentration. The average number of fragrance allergens is twelve per sample; their presence must be indicated in the list of ingredients when its concentration exceeds the 0.001%, but values higher than 1% have been found in some samples. Preservatives data show that parabens, although ubiquitous in other cosmetic products, are not widely used in perfumery. In contrast, the presence of BHT is indeed widespread. The degree of compliance with the European Regulation on the labelling has been evaluated in a subset of samples, and only about the 38% of the perfumes were properly labelled for the allergens tested.

Development of a matrix solid-phase dispersion method for the simultaneous determination of pyrethroid and organochlorinated pesticides in cattle feed.

A matrix solid-phase dispersion (MSPD) method was developed for the simultaneous extraction of 36 common pesticides and breakdown products (mostly pyrethroids and organochlorines) in cattle feed. Different parameters affecting the extraction efficiency (such as dispersing phase, clean-up adsorbent and elution volume) were investigated. The experimental procedure was optimized using a multivariate statistical approach and the final analyses were carried out by GC-muECD. Several protocols for extract purification were also studied. As far as we know, this is the first application of MSPD for the extraction of most of the target pesticides from animal feed. Using the optimized extraction conditions, the method was validated in terms of accuracy, and precision (within-a-day and among-days), using a certified reference material (CRM 115) as well as spiked cattle feedingstuffs at different concentration levels. A matrix effect study was also carried out using various real samples. The recoveries were satisfactory (>75% in most cases) and the quantification limits, at the sub-ngg(-1) or low-ngg(-1) level, complied with the regulated maximum residue levels (MRLs) in animal feed and in main crops used in the preparation of cattle feeding materials. Finally, the MSPD-GC-muECD methodology was applied to the analysis of real cattle feed samples collected in farms of dairy cattle from NW Spain.

Determination of isothiazolinone preservatives in cosmetics and household products by matrix solid-phase dispersion followed by high-performance liquid chromatography-tandem mass spectrometry.

In this work, the development of a new efficient methodology applying, for the first time, matrix solid phase dispersion (MSPD) for the determination of sensitizer isothiazolinone biocides in cosmetics and household products - 2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BzI) and 2-octyl-3-isothiazolinone (OI) - is described. The main factors affecting the MSPD extraction procedure, the dispersive phase and the elution solvent, are assessed and optimized through a multicategorical experimental design, using a real cosmetic sample. The most suitable extraction conditions comprise the use of 2g of florisil as dispersive phase and 5 mL of methanol as elution solvent. Subsequently, the extract is readily analyzed by HPLC-MS/MS without any further clean-up or concentration steps. Method performance was evaluated demonstrating to have a broad linear range (R(2)>0.9980) and limits of detection (LOD) and quantification (LOQ) at the low nanogram per gram level, which are well below the required limits for UE regulation compliance. Satisfactory recoveries above 80%, except for MI (mean values close to 60%), were obtained. In all cases, the method precision (% RSD) was lower than 7%, making this low cost extraction method reliable for routine control. The validated methodology was finally applied to the analysis of a wide variety of cosmetics and household products. Most of the real samples analyzed have been shown to comply with the current European Cosmetic Regulation, although the results obtained for some rinse-off cosmetics (e.g. baby care products) revealed high isothiazolinone content.

Determination of suspected fragrance allergens in cosmetics by matrix solid-phase dispersion gas chromatography-mass spectrometry analysis

An effective low cost sample preparation methodology for the determination of regulated fragrance allergens in leave-on and rinse-off cosmetics has been developed applying, for the first time, matrix solid-phase dispersion (MSPD) to this kind of analytes and samples. The selection of the most suitable extraction conditions was made using statistical tools such as ANOVA, as well as a factorial multifactor experimental design. These studies were carried out using real cosmetic samples. In the final conditions, 0.5 of sample, previously mixed with 1g of anhydrous Na(2)SO(4), were blended with 2g of dispersive sorbent (Florisil), and the MSPD column was eluted with 5 mL of hexane/acetone (1:1). The extract was then analyzed by GC-MS without any further clean-up or concentration step. Accuracy, precision, linearity and detection limits (LODs) were evaluated to assess the performance of the proposed method. Quantitative recoveries (>75%) were obtained and RSD values were lower than 10% in all cases. The quantification limits were well below those set by the international cosmetic regulations, making this multi-component analytical method suitable for routine control. In addition, the MSPD method can be implemented in any laboratory at low cost since it does not require special equipment. Finally, a wide variety of cosmetic products were analyzed. All the samples contained several of the target cosmetic ingredients, with and average number of seven. The total fragrance allergen content was in general quite high, even in baby care products, with values close to or up to 1%, for several samples, although the actual European Cosmetic Regulation was fulfilled.

Development of a method based on sorbent trapping followed by solid-phase microextraction for the determination of synthetic musks in indoor air

Synthetic musks are extensively used as fragrance components in a wide range of consumer and personal care products such as detergents, shampoos, perfumes and other cosmetic products. Amongst them, galaxolide and tonalide have become ubiquitous pollutants due to their continuous releasing into the environment. Because of their nature as artificial fragrances, inhalation should be considered as an important exposure pathway, especially in indoor environments. However, up to now very few studies have been carried out to determine these emergent pollutants indoors. In this work, a simple and highly sensitive methodology for the analysis of synthetic musk fragrances in indoor air samples is presented. The proposed methodology combines solid-phase extraction (SPE) and solid-phase microextraction (SPME), followed by gas chromatography-mass spectrometry (GC/MS). To the best of our knowledge, this is the first method based on SPME for the analysis of musks in air. By active sampling, musks present in air were adsorbed onto 25mg Tenax and then transferred to a SPME fiber in the headspace mode (HS). An experimental design strategy was used to optimize main factors potentially affecting the microextraction process such as fiber coating, temperature and the addition of a microvolume of organic solvent to the solid sorbent prior to SPME. Breakthrough of the SPE sorbent was studied from 1 to 10m(3) without significant losses. Recovery studies were performed at two concentration levels (2 and 20ngm(-3)), obtaining quantitative recoveries (>/=85%) by external calibration. A comprehensive study was performed in order to estimate the limits of detection taking into account the contamination risks and laboratory blanks. Values at the sub ngm(-3) level were achieved for all the target compounds sampling 5m(3) air. External calibration, not requiring the complete sampling process, demonstrated to be suitable for the quantification of all musk compounds. Finally, several indoor environments were analyzed using the proposed method.

Development of a multianalyte method based on micro-matrix-solid-phase dispersion for the analysis of fragrance allergens and preservatives in personal care products☆

An effective, simple and low cost sample preparation method based on matrix solid-phase dispersion (MSPD) followed by gas chromatography-mass spectrometry (GC-MS) or gas chromatography-triple quadrupole-mass spectrometry (GC-MS/MS) has been developed for the rapid simultaneous determination of 38 cosmetic ingredients, 25 fragrance allergens and 13 preservatives. All target substances are frequently used in cosmetics and personal care products and they are subjected to use restrictions or labeling requirements according to the EU Cosmetic Directive. The extraction procedure was optimized on real non-spiked rinse-off and leave-on cosmetic products by means of experimental designs. The final miniaturized process required the use of only 0.1g of sample and 1 mL of organic solvent, obtaining a final extract ready for analysis. The micro-MSPD method was validated showing satisfactory performance by GC-MS and GC-MS/MS analysis. The use of GC coupled to triple quadrupole mass detection allowed to reach very low detection limits (low ng g(-1)) improving, at the same time, method selectivity. In an attempt to improve the chromatographic analysis of preservatives, the inclusion of a derivatization step was also assessed. The proposed method was applied to a broad range of cosmetics and personal care products (shampoos, body milk, moisturizing milk, toothpaste, hand creams, gloss lipstick, sunblock, deodorants and liquid soaps among others), demonstrating the extended use of these substances. The concentration levels were ranging from the sub parts per million to the parts per mill. The number of target fragrance allergens per samples was quite high (up to 16). Several fragrances (linalool, farnesol, hexylcinnamal, and benzyl benzoate) have been detected at levels >0.1% (1,000 μg g(-1)). As regards preservatives, phenoxyethanol was the most frequently found additive reaching quite high concentration (>1,500 μg g(-1)) in five cosmetic products. BHT was detected in eight samples, in two of them (a baby care product and a lipstick) at high concentrations (>1,000 μg g(-1)). Methyl paraben was also found at high levels (>1,700 μg g(-1)) in three leave-on samples. Finally, triclosan was found at the maximum concentration limit (0.3%) laid down by the European regulation in two deodorant samples, and the total paraben concentration was close to the maximum concentration permitted (0.8%) in one leave-on sample (body milk).

Hazardous organic chemicals in rubber recycled tire playgrounds and pavers

In this study, the presence of hazardous organic chemicals in surfaces containing recycled rubber tires is investigated. Direct material analyses using solvent extraction, as well as SPME analysis of the vapour phase above the sample, were carried out. Twenty-one rubber mulch samples were collected from nine different playgrounds. In addition, seven commercial samples of recycled rubber pavers were acquired in a local store of a multinational company. All samples were extracted by ultrasound energy, followed by analysis of the extract by GC-MS. The analysis confirmed the presence of a large number of hazardous substances including PAHs, phthalates, antioxidants (e.g. BHT, phenols), benzothiazole and derivatives, among other chemicals. The study evidences the high content of toxic chemicals in these recycled materials. The concentration of PAHs in the commercial pavers was extremely high, reaching values up to 1%. In addition, SPME studies of the vapour phase above the samples confirm the volatilisation of many of those organic compounds. Uses of recycled rubber tires, especially those targeting play areas and other facilities for children, should be a matter of regulatory concern.