An eco-friendly and stable high-resolution gas chromatography method for high-coverage and simultaneous analysis of polychlorinated dibenzo(p) dioxins/furans (PCDD/Fs) in environmental solid samples: Optimization and validation

The focus of this work was on the optimization and the validation of an eco-friendly and sensitive analytical method for the determination of seventeen polychlorinated dibenzo(p)dioxins/furans (PCDD/Fs) in the soil, sewage sludge, sediment, and flue gas dust samples by using gas chromatography-high-resolution mass spectrometry (GC-HRMS). The optimum and maximum efficient extraction conditions were achieved at 40 mL toluene use (solvent amount), 1.00 min of solvent hold time, and 150 degrees C of extraction temperature. In instrumental method optimization, the conditions of best GC-HRMS efficiency for PCDD/Fs were obtained at 1.5 mL/ min He gas flow and 260 degrees C ion source temperature. Method validation of the optimized GC-HRMS method was carried out considering the basic parameters such as selectivity, sensitivity (limit of detection (LOD) and limit of quantification (LOQ)), linearity, accuracy, precision (intra-day and inter-day reproducibility), trueness, matrix effect, and measurement uncertainty. This method demonstrated quite good linearity between 0.8 pg/g and 6400 pg/g is greater than 0.9984 for all PCDD/Fs. The LOD values ranged from 0.19 pg/g (2378-TCDF) to 0.92 pg/g (OCDD), while LOQs ranged from 0.57 pg/g to 2.76 pg/g. The mean recoveries of accuracy study in sewage sludge were found to be in the range of 84.06 % (1234789-HpCDF) to 100.3 % (OCDD) with RSD of less than 20 %. The results of intra-day precision for PCDD/F congeners changed from 80.95 % (123789-HxCDD) to 108.3 % (123678-HxCDD), whereas their inter-day precision results were determined between 81.03 % (OCDF) to 109.1 % (123789-HxCDF) with RSDs below 20 %. In trueness, the recoveries of PCDD/Fs in industrial sandy soil CRM changed from 81.43 % to 96.12 %. The reported values in PTs exhibited sufficient in terms of z-score values (between +/- 2). The results demonstrated that the sensitivity, accuracy, precision, and trueness of the optimized method for PCDD/F congeners are good and satisfactory by taking into account the standard method performance requirements in the related guidelines. The results indicated no significant matrix effect in sediment, sewage sludge, and soil, while there was a low rate of signal enhancement in flue gas dust. In the measurement uncertainty, the dominant sources of the expanded uncertainty were the reproducibility (23.95-58.51 %) and the repeatability (23.86-52.35 %). Application for the routine monitoring of PCDD/Fs in environmental solids was performed successfully.