Determination of Dechlorane Plus Compounds in Complex Matrix Sludge by GC-MS/MS with Microwave-Assisted Extraction and Evaluation of Treatment Efficiency

Dechlorane plus compounds are present at trace levels (ng/g) in sludge samples. The complex sludge matrix poses a significant challenge for the analysis of these compounds. To address this issue, we established an analytical method for determining dechlorane plus compounds in the sludge of sewage treatment plants, combining microwave-assisted extraction with gas chromatography-triple quadrupole tandem mass spectrometry. Sludge samples were processed using microwave-assisted extraction with online purification, and using acetone-n-hexane (1∶1, V/V) as the extraction solvent. After extraction, GCB/PSA solid-phase extraction columns were used for further purification to reduce matrix interference. The multiple reaction monitoring (MRM) mode of mass spectrometry was employed for accurate quantification. This method demonstrated good linearity (r≥0.998) in the 5−400ng/mL range, with a detection limit of 0.017−0.040ng/g. The average recoveries were 79.8%−99.5%, 86.2%−104.8% and 91.2%−106.1% at low, medium and high concentrations, respectively, with relative standard deviations (RSDs) of <7%. When applied to 11 sewage treatment plants, dechlorane plus compounds were detected, and the contents were relatively high (31.4−195.6ng/g). In sludge, average fsyn of syn-DP was 0.27, lower than that of DP products. This is due to stronger anti-DP adsorption or preferential syn-DP biodegradation. When the A2/O process was adopted, the concentration of dechlorane plus compounds was significantly reduced, and the fsyn value was significantly increased, but the influencing mechanism still needs to be further explored. The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202409190197.