Analysis of non-steroidal anti-inflammatory drugs in milk using QuEChERS and liquid chromatography coupled to mass spectrometry: triple quadrupole versus Q-Orbitrap mass analyzers

We developed a Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method for the high throughput determination of 10 non-steroidal anti-inflammatory drugs (NSAIDs) in milk samples using high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) with a triple quadrupole (QqQ) instrument and an electrospray ionization (ESI) source. The new extraction procedure is highly efficient, and we obtained absolute recoveries in the range 78.1-97.1 % for the extraction and clean-up steps. Chromatographic separation is performed in the gradient mode with a biphenyl column and acidic mobile phases consisting of water and acetonitrile containing formic acid. The chromatographic run time was about 12 min, and NSAID peaks showed a good symmetry factor. For MS/MS detection, we used multiple reaction monitoring (MRM) mode, using ESI in both positive and negative modes. Our method has been validated in compliance with the European Commission Decision 657/2002/EC, and we obtained very satisfactory results in inter-laboratory testing. Furthermore, we explored the use of a hybrid high resolution mass spectrometer, combining a quadrupole and an Orbitrap mass analyzer, for high resolution (HR) MS/MS detection of NSAIDs. We achieved lower NSAID quantification limits with Q-Orbitrap high resolution mass spectrometry (HRMS/MS) detection than those achieved with the QqQ instrument; however, its main feature is its very high selectivity, which makes HRMS/MS particularly suitable for confirmatory analysis

Subproductos halogenados de la cloración en el agua de consumo público Halogenated by-products of chlorination in tap water

Objetivo: La presencia de trihalometanos en el agua de diversas ciudades españolas está demostrada. Este estudio pretende analizar sus concentraciones en el agua de la ciudad de Barcelona. Métodos: Se analizan 151 muestras de agua recogidas durante el año 1998. Los análisis se realizaron en el laboratorio municipal mediante purge and trap y posterior determinación por cromatografía de gases acoplada a espectrofotometría de masas. Los resultados se presentan según el origen del agua: ríos Llobregat, Ter o mezcla. Resultados: En aguas del Ter los valores son relativamente bajos y predominan cloroformo y bromodiclorometano, mientras que en las del Llobregat son más elevados y predominan bromoformo y dibromoclorometano. Las aguas de mezcla presentan valores intermedios. Los valores totales alcanzados en las muestras procedentes del Llobregat superan los 100 µg/l. Conclusiones: Estos resultados muestran la necesidad de seguir corrigiendo la contaminación orgánica y los compuestos halogenados en el agua captada para el consumo humano en Barcelona.Objective: The presence of trihalomethanes in the water systems of several Spanish cities has been demonstrated. The aim of this study was to analyze trihalomethane concentrations in the water provided for human consumption in the city of Barcelona. Methods: We analyzed 151 water samples collected in 1998. The analyses were performed in the Public Health Laboratory of Barcelona using the purge-and-trap method and subsequent determination by gas chromatography and mass spectrometry. The results are presented according to the source of the water: the rivers of Llobregat or Ter, or a mixture of these. Results: Thrihalomethane concentrations in the water from Ter were relatively low, with a predominance of chloroform and bromodichloromethane, while concentrations in the water from Llobregat were much higher, with a predominance of bromoform and dibromochloromethane. Mixed water showed intermediate concentrations. The total concentrations reached in the water from Llobregat were above 100 µg/l. Conclusions: The results show the need to continue reducing organic pollution and halogenated compounds in the water used for human consumption in Barcelona

A fully validated method for the determination of arsenic species in rice and infant cereal products

A full validation of inorganic arsenic (iAs), methylarsonic acid (MA), and dimethyl arsinic acid (DMA) in several types of rice and rice-based infant cereals is reported. The analytical method was developed and validated in two laboratories. The extraction of the As species was performed using nitric acid 0.2 % and hydrogen peroxide 1 %, and the coupled system liquid chromatography-inductively coupled plasma-mass spectrometry (LCICP-MS) was used for speciation measurements. Detection limit (DL), quantification limit, linearity, precision, trueness, accuracy, selectivity, as well as expanded uncertainty for iAs, MA, and DMA were established. The certified reference materials (CRMs) (NMIJ 7503a, NCS ZC73008, NIST SRM 1568a) were used to check the accuracy. The method was shown to be satisfactory in two proficiency tests (PTs). The broad applicability of the method is shown from the results of analysis of 29 samples including several types of rice, rice products, and infant cereal products. Total As ranged from 40.1 to 323.7 μg As kg-1. From the speciation results, iAs was predominant, and DMA was detected in some samples while MA was not detected in any sample

Plaguicidas en la dieta: aportando piezas al rompecabezas Pesticides in the diet: adding pieces to the puzzle

Objetivos: Mejorar la información sobre la exposición a plaguicidas mediante la dieta en nuestro país con la presentación de los resultados de detección de 88 parámetros de plaguicidas en 1.109 muestras de alimentos, obtenidas entre 1998 y 2003 para el programa de Investigación de la Calidad Sanitaria de los Alimentos (ICSA) de Barcelona. Material y método: Se presentan los resultados por grupos de alimentos y se comparan con la situación en el período anterior para frutas y hortalizas. La significación de las diferencias observadas se estima mediante la prueba de la &#967;². Resultados: En las 1.109 muestras analizadas se obtuvieron 116 resultados positivos para plaguicidas (10,5%). En el 1,5% de las muestras se detectaron halogenados persistentes y en el 14,4%, otros plaguicidas. Los positivos se concentran en frutas, hortalizas, especias y cereales y sus derivados. No hay positivos entre los aceites vegetales, los huevos ni los productos de la pesca, y casi no hay en los lácticos ni en los cárnicos. Las frutas concentran la mayor presencia de plaguicidas, en todos los casos no persistentes. Las hortalizas tienen menos plaguicidas, pero en ellas se detecta algún tipo de organoclorado. Al comparar los valores en las frutas y verduras con los de 1989-1997 no se aprecian diferencias que alcancen la significación estadística. Conclusiones: Aunque el volumen de muestras con plaguicidas es relevante, en su mayoría no son por productos halogenados persistentes. Destaca la elevada presencia de plaguicidas en la fruta.<br>Objectives: To improve information on exposure to pesticides through diet in Spain by reporting the results on 88 pesticide parameters in 1,109 food samples obtained between 1998 and 2003 as part of the Barcelona program for research on the health quality of foods. Material and method: The results are presented by food groups. For fruits and vegetables, the results were compared with those for the previous period. Statistical comparisons were performed using the &#967;2 test. Results: Of the 1,109 samples, 116 were positive for pesticides (10.5%). Persistent chlorinated compounds were detected in 1.5% and other compounds were found in 14.4%. Positive results were concentrated in fruits, vegetables, spices, cereals and their derivatives. There were no positive results among vegetable oils, eggs or fish products, and almost none in dairy products and meats. Fruits contained the greatest number of pesticides but none were persistent. Vegetables contained fewer pesticides, but some of these were persistent chlorinated compounds. Comparison of the results for fruits and vegetables with those of the 1989-97 period revealed no significant trends. Conclusions: Although a considerable number of samples contained pesticides, most of these were not persistent chlorinated compounds. The number of pesticides in fruits was notable

A need for determination of arsenic species at low levels in cereal-based food and infant cereals. Validation of a method by LC-ICPMS.

The present study arose from the need to determine inorganic arsenic (iAs) at low levels in cereal-based food. Validated methods with a low limit of detection (LOD) are required to analyse these kinds of food. An analytical method for the determination of iAs, methylarsonic acid (MA) and dimethylarsinic acid (DMA) in cereal-based food and infant cereals is reported. The method was optimised and validated to achieve low LODs. Ion chromatography-inductively coupled plasma mass spectrometry (LC-ICPMS) was used for arsenic speciation. The main quality parameters were established. To expand the applicability of the method, different cereal products were analysed: bread, biscuits, breakfast cereals, wheat flour, corn snacks, pasta and infant cereals. The total and inorganic arsenic content of 29 cereal-based food samples ranged between 3.7-35.6 and 3.1-26.0 microg As kg-1, respectively. The present method could be considered a valuable tool for assessing inorganic arsenic contents in cereal-based foods