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Desenvolvimento e validação de um método para a quantificação de compostos orgânicos voláteis (COVs) em solos
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| 4.53 MB | Adobe PDF |
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Abstract(s)
O presente trabalho teve como objetivo o desenvolvimento e validação de um método analítico por cromatografia gasosa acoplada à espetrometria de massa, utilizando a técnica headspace estático (HS-GC-MS) para a quantificação de compostos orgânicos voláteis (COVs) em amostras de solo. Foram estudados 38 compostos, seguindo os requisitos da norma EN ISO 22155:2016, da NP EN ISO/IEC 17025:2019, da ISO 8466-1:2021, do guia RELACRE 13 e do Guia Técnico da APA, tendo em conta os valores de referência legais (VLR) estabelecidos. De forma a confirmar a adequabilidade do método aos objetivos do laboratório foram avaliados os seguintes parâmetros: condições ótimas de extração, tempo de retenção dos analitos, seleção de massas dos iões, seleção de padrões internos, linearidade, gama de trabalho, seletividade, limite de quantificação (LOQ), limite de deteção (LOD), precisão (repetibilidade e precisão intermédia) e
exatidão. Para a extração dos analitos foram otimizadas várias condições, como a temperatura de extração (70 °C), volume da amostra (10 mL) e o tipo de água (água mineral natural). A gama de trabalho de [0,2–3,2] mg/L foi definida para a maioria dos compostos, e [0,1–3,2] mg/L para hexacloroetano e hexaclorobutadieno. A linearidade foi confirmada por meio de curvas de calibração com coeficientes de determinação (R²) superiores a 0,998 e pela aplicação do
teste de Mandel. Os LOQs estabelecidos foram confirmados tanto teoricamente como experimentalmente, sendo compatíveis com os requisitos do Guia Técnico da APA. A precisão do método foi confirmada por coeficiente de variação inferior a 30% em todas as condições estudadas, à exceção do hexano, cuja validação foi parcialmente comprometida devido a contaminação ambiental. A exatidão foi avaliada por ensaios de recuperação com resultados dentro do intervalo aceitável de 70% a 130%, garantindo a exatidão e a seletividade do método. Os resultados obtidos para os parâmetros de validação permitem concluir que o método se encontra validado para todos os compostos exceto o hexano.
This study aimed to develop and validate an analytical method using gas chromatography coupled with mass spectrometry, employing the static headspace technique (HS-GC-MS) for the quantification of volatile organic compounds (VOCs) in soil samples. A total of 38 compounds were analyzed in accordance with the requirements of EN ISO 22155:2016, NP EN ISO/IEC 17025:2019, ISO 8466-1:2021, RELACRE Guide 13, and the APA Technical Guide, considering the established legal reference values (LRVs). To confirm the method’s suitability for the laboratory’s objectives, the following parameters were evaluated: optimization of extraction conditions, analyte retention time, ion mass selection, internal standard selection, linearity, working range, selectivity, limit of quantification (LOQ), limit of detection (LOD), precision (repeatability and intermediate precision), and accuracy. Several conditions were optimized for analyte extraction, including extraction temperature (70 °C), sample volume (10 mL), and water type (natural mineral water). A working range of [0.2–3.2] mg/L was established for most compounds, and [0.1–3.2] mg/L for hexachloroethane and hexachlorobutadiene. Linearity was confirmed through calibration curves with coefficients of determination (R²) exceeding 0.998 and by applying Mandel’s test. The established LOQs were confirmed both theoretically and experimentally and were compliant with the APA Technical Guide requirements. Method precision was verified by a coefficient of variation below 30% under all studied conditions, except for hexane, whose validation was partially compromised due to environmental contamination. Accuracy was assessed through recovery tests, with results falling within the acceptable range of 70% to 130%, thereby ensuring the method’s accuracy and selectivity. The validation results confirm that the method is validated for all compounds except hexane.
This study aimed to develop and validate an analytical method using gas chromatography coupled with mass spectrometry, employing the static headspace technique (HS-GC-MS) for the quantification of volatile organic compounds (VOCs) in soil samples. A total of 38 compounds were analyzed in accordance with the requirements of EN ISO 22155:2016, NP EN ISO/IEC 17025:2019, ISO 8466-1:2021, RELACRE Guide 13, and the APA Technical Guide, considering the established legal reference values (LRVs). To confirm the method’s suitability for the laboratory’s objectives, the following parameters were evaluated: optimization of extraction conditions, analyte retention time, ion mass selection, internal standard selection, linearity, working range, selectivity, limit of quantification (LOQ), limit of detection (LOD), precision (repeatability and intermediate precision), and accuracy. Several conditions were optimized for analyte extraction, including extraction temperature (70 °C), sample volume (10 mL), and water type (natural mineral water). A working range of [0.2–3.2] mg/L was established for most compounds, and [0.1–3.2] mg/L for hexachloroethane and hexachlorobutadiene. Linearity was confirmed through calibration curves with coefficients of determination (R²) exceeding 0.998 and by applying Mandel’s test. The established LOQs were confirmed both theoretically and experimentally and were compliant with the APA Technical Guide requirements. Method precision was verified by a coefficient of variation below 30% under all studied conditions, except for hexane, whose validation was partially compromised due to environmental contamination. Accuracy was assessed through recovery tests, with results falling within the acceptable range of 70% to 130%, thereby ensuring the method’s accuracy and selectivity. The validation results confirm that the method is validated for all compounds except hexane.
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Keywords
Headspace extraction Gas chromatography Mass spectrometry Validation Volatile organic compounds Extração headspace Cromatografia gasosa Espetrometria de massa Validação Compostos orgânicos voláteis