The herbicide glyphosate is the most widely used pesticide worldwide. Glyphosate and its major metabolite, aminomethylphosphonic acid (AMPA), have been frequently found in water samples. The widely used methods for determining these compounds are expensive and environmentally unfriendly due to reagent consumption for derivatization. Another possibility is the use of classic ion chromatography, albeit with low sensitivity and subject to interferences. Therefore, this study aimed to develop a method to directly and simultaneously determine glyphosate, AMPA, and common inorganic anions in water samples using gradient capillary ion chromatography without sample pre-treatment and derivatization. The proposed method was validated, presenting adequate linearity for glyphosate and AMPA with a determination coefficient (r2) > 0.998. Recoveries ranged from 94 to 105% and 79 to 113% for glyphosate and AMPA, respectively, with a relative standard deviation < 10%. The practical method limits of detection and quantification for both glyphosate and AMPA were 7.5 and 25 µg L 1, respectively. The method presented satisfactory results for the anions fluoride, chloride, bromide, nitrite, nitrate, phosphate, and sulfate, with limits of detection ranging from 7.5 to 200 µg L-1. Application of the method in water samples proved simple, efficient, and cost-effective, enabling the monitoring of these analytes in different water matrices.

To preserve human health, persistent organic pollutants (POPs) and current-use pesticides (CUPs) should be monitored in fatty tissues, including breast milk. Therefore, this study aimed to optimize sample preparation conditions using a 32 factorial design for the determination of POPs and CUPs by gas chromatography coupled to mass spectrometry with negative chemical ionization (GC-NCI-MS). The method was validated for 57 POP and CUP compounds using hexane:acetone for extraction and clean-up by dispersive solid phase extraction (d-SPE) with Florisil®. The matrix effect was compensated by extracted analytical calibration. Method validation showed satisfactory results with limits of detection of 3 to 13 ng g-1 of fat. The method presented adequate accuracy (recoveries from 72 to 117%) and precision (relative standard deviation (RSD) ≤ 18%) and was applied to breast milk samples from Rio Grande do Sul State, southern Brazil, wherein all samples contained at least one compound. With principal component analysis, it was possible to associate the pesticides detected with the city of origin of the samples and the number of pregnancies of nursing mothers. Additionally, the analytical method was effective for the determination of trace levels of POPs and CUPs in breast milk and can be applied in biomonitoring studies.

A fast and sensitive method using high performance liquid chromatography-fluorescence detection (HPLC-FD) and ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) was developed and validated for the determination of avermectins residues in ovine muscle samples. QuEChERS (quick, easy, cheap, effective, rugged and safe) sample preparation based on acetonitrile extraction followed by partitioning with NaCl and Na2SO4 and dispersive solid-phase extraction (d-SPE) clean-up with C18 was applied. Na2SO4 was used instead of MgSO4 due to lower amounts of co-extractives in the final extract. The procedure was validated according to the Commission Decision 2002/657/EC. The method showed determination coefficients (r2) higher than 0.99, recoveries between 93.2 and 124.3% for spike levels between 0.5 and 2.0 times the maximum residues limit (MRL) values. The repeatability and intermediate precision RSD values ranged from 1 to 19%. Decision limits (CCα) and detection capabilities (CCβ) ranged from 10.7 to 59.4 µg kg-1 and 11.4 to 68.8 µg kg-1, respectively. Method performance was successfully evaluated by analyzing real samples and proficiency test with a z-score in the range of ±1.

An easy and efficient sample preparation method was developed for the determination of natamycin residues in wine samples by solvent extraction and ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) analysis. After choosing acetonitrile as extraction solvent, an experimental design was carried out with different amounts of C18 and primary secondary amine (PSA) sorbents in order to optimize the clean-up step. Validation results were satisfactory, with recoveries from 77 to 95% and relative standard deviation (RSD) lower than 10% for the spike levels 5, 10 and 20 µg L-1. Method limit of detection (LOD) and quantification (LOQ) were 1.5 and 5.0 µg L-1, respectively. The validated method proved to be an excellent analytical tool, with a total analysis time of 3 min. The method was applied in 10 Brazilian wine samples and no residues of natamycin were detected.

An effective analytical method for pesticides multiresidue determination in grape samples was developed and validated. A modified quick, easy, cheap, effective, robust and safe (QuEChERS) method was used to extract the target compounds. Several sorbent materials were tested for the clean-up step using dispersive solid phase extraction (d-SPE) and Florisil® was selected. Samples extracts were evaporated before injection in the gas chromatography with mass spectrometry (GC-MS) system in order to improve detectability. Recoveries from blank samples spiked at 0.04, 0.3 and 1.0 mg kg−1 ranged from 95 to 102% with relative standard deviation (RSD) from 1.3 to 19.7%. Method limits of detection (LODm) and quantification (LOQm) ranged from 0.006 to 0.012 and 0.02 to 0.04 mg kg−1, respectively. The positive matrix effect caused an increase in the peak areas of all compounds and matrix matched calibration curve linearity (coefficient of determination, r2) was higher than 0.98 for all target analytes. The validated method was successfully applied for the determination of 19 pesticides in grape samples.

In this work, a method for multiclass determination of 70 pesticides residues with different properties in drinking water using solid phase extraction (SPE) with polymeric sorbent and determination by gas and liquid chromatography coupled to tandem mass spectrometry (GC-MS/MS and LC-MS/MS) was developed and validated. Different sample volumes, sorbents and elution solvents were evaluated. The best results were obtained using the sorbent Oasis® HLB, sample acidified at pH 2.5 and a mixture of dichloromethane/methanol as eluent. The limit of quantification (LOD) of the method was 0.02 µg L-1 for aldrin, dieldrin and chlordane and 0.5 µg L-1 for the other compounds. Satisfactory accuracy, with recoveries between 70 and 117.3%, and good precision, with relative standard deviation (RSD) values below 19.7% for most of the compounds, were achieved. The validated method was applied to real water samples and results indicated that the proposed method is suitable for the determination of pesticide residues in water samples.

O mel pode apresentar resíduos de pesticidas devido à contaminação das abelhas durante a coleta de pólen e néctar ou por tratamento das colmeias. Assim, a determinação de resíduos de pesticidas em mel é de grande importância, apesar da dificuldade devido à complexidade da matriz. Neste estudo, um novo método para a determinação de pesticidas de diferentes grupos químicos em mel foi desenvolvido e validado. Amostras de mel foram extraídas pelo método QuEChERS modificado e analisados por cromatografia gasosa com detecção por captura de elétrons (GC-ECD). Os resultados de recuperação, avaliados em três níveis de fortificação, foram entre 71 e 119% para a maioria dos compostos, com valores de desvio padrão relativo (RSD) < 20%. O método proposto permite a determinação com limites de detecção entre 3 e 6 µg kg-1, combinando a extração e limpeza do extrato de forma efetiva, com boa sensibilidade e seletividade, e foi aplicado com sucesso na análise de amostras comerciais de mel.

Honey can present pesticide residues due to the contamination of bees during the collection of pollen and nectar or by treatment of hives. Thus, the determination of pesticide residues in honey is of great importance, despite the difficulty due to the complexity of the matrix. In this study a new method for the determination of pesticides from different chemical groups in honey was developed and validated. Honey samples were extracted by modified QuEChERS method and analyzed by gas chromatography with electron capture detection (GC-ECD). Recovery results, evaluated at three spike levels, were between 71 and 119% for most of the compounds, with relative standard deviation (RSD) < 20%. The proposed method enables the determination at limits of detection between 3 and 6 µg kg-1, combining effective extraction and clean-up steps with good sensitivity and selectivity, and was successfully applied to the analysis of commercial honey samples.

Considering the possibility that pesticides used in cattle raising produce residues in milk and cause harm to public health, this study developed a multiresidue method for determination of pesticide residues in bovine milk, using a modified QuEChERS method for sample preparation, and quantification by GC-MS/MS. The method proved to be efficient, resulting in satisfactory recoveries in the range 71.1 to 117.4%, for 45 of the 48 compounds analyzed with RSD values < 17.3%. The method LOD and LOQ were3.0 and 10.0 µg L-1, respectively, except for cyfluthrin which showed 7.5 and 25.0 µg L-1.

Um método eficiente e sensível para a determinação simultânea do inseticida fipronil e seus principais metabólitos fipronil desulfinil, fipronil sulfeto e fipronil sulfona em águas superficiais foi desenvolvido e validado. Fipronil e seus metabolitos foram determinados por cromatografia gasosa com detecção por captura de elétrons (GC-ECD) após uma etapa de pré-concentração empregando extração em fase sólida (SPE). Os parâmetros de validação avaliados incluíram curva analítica e linearidade, limites de detecção (LOD) e de quantificação (LOQ), precisão e exatidão. GC-ECD apresentou uma boa resposta para fipronil e seus metabólitos, e todas as curvas analíticas apresentaram coeficientes de determinação superiores a 0,995. Os LODs do método foram 2,5 ng L-1 para fipronil e 2,0 ng L-1 para cada metabólito. Todos os valores de recuperação variaram de 81,3 a 112,3%, com valores de desvio padrão relativo (RSD) inferiores a 14,2%. O método proposto foi aplicado com sucesso em amostras de água de lavoura de arroz irrigado.

An efficient and sensitive method for simultaneous determination of the insecticide fipronil and its main metabolites fipronil desulfinyl, fipronil sulfide and fipronil sulfone in surface water was developed and validated. Fipronil and its metabolites were determined by gas chromatography with electron capture detection (GC-ECD) after a preconcentration step using solid phase extraction (SPE). The evaluated validation parameters included analytical curve and linearity, limit of detection (LOD) and quantification (LOQ), precision and accuracy. GC-ECD presented a good response for fipronil and its metabolites, and all analytical curves showed determination coefficients higher than 0.995. The LOD values of the method were 2.5 ng L-1 for fipronil and 2.0 ng L-1 for each metabolite. All recovery values were between 81.3 and 112.3%, with relative standard deviation (RSD) values lower than 14.2%. The proposed method was successfully applied to the analysis of water samples from flooded rice fields.

The determination of veterinary drug residues in foods of animal origin is an important issue because of the risk these compounds pose to human health in addition to their persistence and tendency to bioaccumulate. In recent years, significant progress has been made in the area and this review presents the state of the art in sample preparation procedures associated with chromatographic techniques coupled to mass spectrometry for multiresidue determination of veterinary drugs in food of animal origin at concentration levels suitable for the control of residues and contaminants in food.

Neste trabalho desenvolveu-se um método para a determinação de 15 pesticidas em pão utilizando cromatografia gasosa acoplada à espectrometria de massas (GC-MS), operando no modo de ionização química negativa (NCI). No preparo da amostra utilizou-se acetonitrila contendo 1% (v/v) de ácido acético, na presença de acetato de sódio, citrato de sódio e sulfato de magnésio. O método foi validado avaliando os seguintes parâmetros: linearidade, limite de detecção (LOD), limite de quantificação (LOQ), precisão e exatidão. A faixa linear utilizada foi de 1,0-100 µg L-1. As recuperações foram consideradas satisfatórias apresentando valores entre 70 e 117%, com RSD < 17,6% para quase todos os compostos. O LOQ do método variou de 10 a 20 µg kg-1. O método demonstrou ser adequado, sensível e altamente seletivo para a análise multirresíduo de pesticidas em pão.

In this work a method for the determination of 15 pesticides in bread samples using gas chromatography coupled with mass spectrometry (GC-MS), operating in the negative chemical ionization mode (NCI) was developed and validated. For the extraction procedure acetonitrile containing 1% (v/v) acetic acid was used in presence of sodium acetate, sodium citrate and magnesium sulphate. The method was validated evaluating the following parameters: linearity, limit of detection (LOD), limit of quantification (LOQ), precision and accuracy. The linear range used was from 1.0 to 100 µg L-1. The recoveries had been considered satisfactory presenting values between 70 and 117% with RSD < 17.6% for almost all the compounds. The real method LOQ ranged from 10 to 20 µg kg-1. The method shown to be adequate for the multiresidue analysis of pesticides in bread and the GC-MS (NCI) proved to be sensitive and highly selective.

A new method is described for the determination of the herbicide bispyribac-sodium in surface water, especially from river and irrigated rice water samples. The method involves extraction in solid phase and quantification by high performance liquid chromatography with diode array detection (HPLC-DAD). After optimization of the extraction and separation parameters, the method was validated. The method presented average recoveries of 101.3 and 97.7%, under repeatability and intermediate precision conditions, respectively, with adequate precision (RSD from 0.9 to 7.5%). The method was applied for the determination of bispyribac-sodium in surface water samples with a limit of detection of 0.1 μg L-1.

This review attempts to provide an updated overview of the Quick, Easy, Cheap, Effective, Ruged and Safe (QuEChERS) multiresidue extraction method, that involves initial extraction in acetonitrile, an extraction/partition step after the addition of salt, and a cleanup step utilizing dispersive solid phase extraction. QuEChERS method is nowadays the most applied extraction method for the determination of pesticide residues in food samples, providing acceptable recoveries for acidic, neutral and basic pesticides. Several applications for various food matrices (fruits, vegetables, cereals and others) in combination with chromatographic mass spectrometry analysis were presented.

Neste trabalho, um método usando extração em fase sólida e cromatografia a gás acoplada à espectrometria de massas no modo de monitoramento seletivo de íons, foi desenvolvido e validado para a determinação multiclasse de 20 pesticidas regulados pela legislação brasileira para água potável. Como estes pesticidas devem ser determinados em baixas concentrações, um elevado fator da pré-concentração associado à sensibilidade elevada da análise cromatográfica foi necessário. O método apresentou limites de quantificação entre 0,003 e 0,093 µg L-1. A maioria dos compostos apresentou recuperações médias entre 51 e 116%. Embora a natureza química distinta dos pesticidas analisados dificulte a obtenção de boa recuperação para todos os compostos avaliados, a precisão dos resultados foi excelente. A seletividade do método foi avaliada através da intensidade relativa dos íons de quantificação e de qualificação, sendo considerada adequada. A análise em amostras reais cumpriu os critérios para a qualificação instrumental e a avaliação da conformidade do sistema.

In this work, a method using solid-phase extraction and gas chromatography coupled mass spectrometry in the selective ion monitoring (SIM) mode was developed and validated for the multi-class determination of 20 pesticides regulated by the Brazilian legislation for drinking water. Because these pesticides must be determined at low concentrations, a high preconcentration factor associated to the high sensitivity of chromatographic analysis was necessary. The method presented quantification limits between 0.003 and 0.093 µg L-1. Most of the compounds presented mean recoveries between 51 and 116%. Although the differing chemical nature of the pesticides analyzed difficult the attainment of good recovery for all of the compounds evaluated, the precision of the results was excellent. The selectivity of the method was evaluated through the relative intensity of quantification and qualification ions and was considered adequate. Analysis in real samples met criteria for instrumental qualification and the system suitability evaluation.

Este estudo avaliou a degradação do herbicida clomazone em água destilada e de campos de arroz irrigado, através de irradiação UV e sob condições naturais. Após a etapa de pré-concentração por extração em fase sólida (SPE), a concentração remanescente foi determinada por cromatografia líquida de alta eficiência com detecção por arranjo de diodos (HPLC-DAD) e a identificação dos produtos de degradação foi efetuada por cromatografia gasosa com espectrometria de massas (GC-MS). Sob irradiação UV, o clomazone foi degradado mais rapidamente na água destilada que na água de superfície. Na água de irrigação, sob luz solar, o clomazone apresentou tempo de meia-vida médio de 3,2 dias em três safras consecutivas, e após a aplicação a concentração na água permaneceu acima de 0,1 μg L-1 por cerca de 20 dias. Diversos subprodutos, tais como 2-clorobenzaldeído e 2-clorobenzeno metanol, foram identificados por GC-MS, evidenciando que a concentração dos intermediários aumentou no início e então eles também sofreram degradação.

This study evaluated the degradation of the herbicide clomazone in distilled water and from irrigated rice fields, through UV irradiation and under natural conditions. After a solid phase extraction (SPE) as preconcentration step, the remained concentration of clomazone was determined by high performance liquid chromatography with diode array detection (HPLC-DAD) and the identification of the degradation products was achieved by gas chromatography-mass spectrometry (GC-MS). Under UV irradiation, the clomazone was degraded faster in distilled water than in surface water. In irrigated rice water, under sunlight irradiation, clomazone presented a half-life time average of 3.2 days in three consecutive harvests, and after application the concentration in water remained higher than 0.1 μg L-1 for 20 days. Several by-products, like 2-chlorobenzaldehyde and 2-chlorobenzene methanol, were identified by GC-MS, which evidenced that the concentration of intermediates at the begining increase and then they also undergo degradation.