The dielectric barrier discharge ionization detector (BID) is one of the most modern detectors commercially available for gas chromatography (GC). Its technology based on the sample ionization through the energy released from the helium plasma generation process gives it the ability to act as a universal detector and a greater response to various types of compounds compared to the well-established flame ionization detector (FID). In this study, polycyclic aromatic hydrocarbons (PAHs), organophosphates (OPPs) and organochlorines pesticides (OCPs) were investigated. The parameters that could explain the performance of the BID and FID detectors were: structural factors, ionization energy (IE) and energy of the highest occupied molecular orbital (EHOMO), which were obtained by density functional theory (DFT). The relative (BID/FID) responses to PAHs and pesticides were about 1.8 and 3.0 times greater than FID, respectively. Less structural dependence of the BID signal compared to the FID signal was observed. Among the parameters calculated by DFT, the IE was the one that most seemed to have influenced the response of the two detectors studied. The theoretical data proved to be quite consistent to explain the trends observed experimentally, especially to the BID.

This work focuses on the validation and application of solid phase extraction followed by high-performance liquid chromatography (SPE-HPLC) analysis of important endocrine disruptors compounds (EDC) from different classes in highly complex wastewater matrix. The endocrine disruptors investigated included three different categories: pharmaceuticals (sulfamethoxazole (SMZ), trimethoprim (TMP) and diclofenac (DCF)), hormones (estrone (E1), 17α-ethinylestradiol (EE2) and 17β-estradiol (E2)) and plastic materials (bisphenol A (BPA)). The method involves pre-concentration by SPE using Strata-X extraction cartridges followed by HPLC coupled with diode array detector (DAD). As the assumption of homoscedasticity was met for analytical data, ordinary linear regression procedure was applied to the data. The method was considered validated for 7 EDC after consistent evaluation of the key analytical parameters. Recoveries were ranged from 52.3 to 179.6%. Limits of quantification were in the range 6.0-0.4 µg L−1. The described method was applied to evaluate the occurrence and removal efficiency of EDC in two biological sewage treatment plants (STPs). The influent mean concentrations of E1, E2 and EE2 hormones were 79.54; 175.09 and 102.19 µg L−1, respectively, while for SMZ, TMP, DCF and BPA were 215.17; 187.01; 218.97 and 87.12 µg L−1 for STP A, respectively. The efficiencies for the removal of EDCs ranged from 0 to 79.4%.

A method based on QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction and gas chromatography-mass spectrometry (GC-MS) detection was described for the pesticides dichlorvos, disulfoton, ethoprophos, parathion methyl, fenchlorphos, chlorpyrifos, azinphos methyl and prothiofos in sapodilla. For all compounds studies, it was observed a strong matrix effect showing the need to use matrix matched calibration strategy. Method was validated, and good linearity (R > 0.99) was obtained for all pesticides studied with limits of detection (LODs) and quantification (LOQs) ranging from 0.01 to 0.06 mg kg-1 and 0.03 to 0.2 mg kg-1, respectively. Recovery studies were performed at different levels (0.08, 0.10, 0.14, 0.20, 0.35 and 1.17 mg kg-1) and showed good results (between 70 and 120% with relative standard deviation (RSD) < 20%). A statistical test was applied to the coefficients of the analytical curves obtained in the sapodilla matrix. Analyses of commercial samples showed chlorpyrifos were detected in about 70 and 33% for fruit and pulps samples, respectively. It should be noted that chlorpyrifos is not permitted in sapodilla crops by ANVISA and EC guidelines.

Perfumes are products mainly consisting of ethyl alcohol, water and fragrance. These fragrances are responsible for characterizing the pleasant and unique odor of each perfume. Among the fragrances, we highlight a group of fragrances which can cause contact allergy, leading to dermatitis. Brazilian and the European law state that when these concentrations of allergenic fragrances exceed the limit of 0.01% for non-rinse products and 0.001% for products with rinsing, the manufacturer is obliged to discriminate on its label their presence. This work aims to quantify allergic fragrances in original and Brazilian perfume using solid-phase microextraction and analyze by gas chromatography-mass detector.