Screening of 50 Emerging Contaminants in Wastewater by Micro-direct-injection UPLC-MS/MS

Abstract

In recent years, with the increasingly serious problem of environmental pollution, people′s awareness of environmental protection has gradually strengthened. In addition to the monitoring of conventional pollutants such as heavy metals and pesticides, the monitoring scope has been extended to emerging contaminants (ECs), which have the potential to cause known or suspected adverse for ecological or human health effects. Recently, a new group of compounds has been added to the anthropological-based pollutants, which are illicit drugs. The main source of these residues is from consumers. After ingestion of the illicit drug dose, active parent compounds and their metabolites are excreted through urine, entering urban wastewater and reaching wastewater treatment plants (WWTPs). These substances may have low removal efficiencies and persist in the treated wastewater. Though the concentrations of emerging contaminants in environment are low, the risks for human health and environment cannot be excluded. Considering the serious threat posed by these substances, our country has clearly put forward the work deployment of “paying attention to the treatment of new pollutants”. Current analytical methods developed for the determination of trace level of compound in wastewater samples usually include pre-concentration steps, the most common being those based on solid-phase extraction (SPE) and online-SPE. However, there are many disadvantages of SPE, such as laborious, time-consuming, cost-consuming and needing specialized instrumentation. Therefore, the convenient and fast methods need to be developed, which can meet the high-sensitivity analysis requirements of wastewater detection. Here, a method of micro-direct-injection ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the rapid screening of 50 emerging contaminants. The wastewater samples were centrifuged at 13 500 r/min for 3 min, the supernatants were filtered through PTFE filters before injection into the UPLC-MS/MS system. A Waters Acquity UPLC HSS T3 column (100 mm×2.1 mm×1.8 μm) was used, the mobile phases were 5 mmol/L ammonium acetate-0.01% formic acid (A) and acetonitrile (B). The result showed that the limits of detection (LODs) of 50 targets were 0.1-5 ng/L, the extraction recovery was 65.4%-113.9%, and the matrix effect was 64.8%-139.8%. The methamphetamine, codeine, morphine, ketamine, tramadol, O-demethyltramadol and 2-fluoro-deschloroketamine were detected in the real wastewater sample. This method can rapidly and simply screen the trace amounts of a variety of emerging contaminants in wastewater samples.

Keywords

• micro-direct-injection
• ultra-high performance liquid chromatography-tandem mass spectrometry (uplc-ms/ms)
• emerging contaminants (ecs)
• wastewater