Determination of emerging contaminants in biological matrices using gas chromatography coupled to an electron capture detector (GC-ECD)

Contaminants are a diverse group of chemical substances, such as pharmaceutical chemicals, personal care products, pesticides, flame retardants, microplastics, artificial sweeteners, etc. The literature on these compounds reveals serious harmful effects on human health and the ecosystem due to the particular characteristics of each one and their interaction with the environment. Thus, the objective of this work is to develop and validate an instrumental method for the analysis of organohalogenated compounds and to evaluate the levels of contaminants in biological matrices of muscle tissue of aquatic organisms. In the methodology of this work, some parameters of the gas chromatograph coupled to an electron capture detector (GC-ECD) were explored, in which gradients were constructed in the oven, flow and injection temperature, in order to optimize the separation and identification of the substances. Once the chromatographic conditions were optimized, it was possible to establish a method that allowed the separation and determination of 47 compounds in 70 min of analysis. In the validation of the resulting method, selectivity was ensured by analyzing equipment blanks in which there were no significant peaks, while the linearity of each compound generated analytical curves with correlation coefficients greater than 0.99. The detection limits (LOD) and quantification limits (LOQ) were calculated according to the methodology that resulted in the range of 0.01 to 3.93 ng mL-1 for the LD, while for the LQ the range constituted 0.02 to 11.91 ng mL-1. The precision had acceptable and satisfactory results according to the analytical method validation guides available in the literature, as well as the accuracy, which was evaluated by means of recovery tests in samples doped with the standards. In this way, the validation of the chromatographic method for the identification and quantification of emerging contaminants through GC-DCE was achieved, since all the established criteria are in accordance with INMETRO as well as other agencies such as ANVISA. After validation, the method was applied to analyses of fish, crab and oyster samples, that is, the levels of target contaminants were assessed in real samples that demonstrate concern both in terms of public health related to the consumption of aquatic organisms and environmental contamination.