A high-efficiency nanofiltration osmotic pump - coupled solid phase extraction sampler for in situ sampling and enrichment of pharmaceuticals and personal care products (PPCPs) in wastewater

Samplers utilizing external power-free osmotic pumps, rather than electric driven pumps, have been successfully used in river water sampling to determine time-weighted average concentrations. However, the insufficient flow rate (< 100 mL/d) driven by the reverse osmosis module poses challenges in meeting the sampling volume requirements for enrichment of trace micropollutants such as pharmaceuticals and personal care products (PPCPs). In this study, a novel nanofiltration osmotic pump (NOP), constructed with nanofiltration membrane combined with a draw solution of MgSO 4 , significantly increased the sampling flow rates to 500–1400 mL/d, effectively enhancing its prospects for application in micropollutant sampling. The coupling of NOP with a solid phase extraction (SPE) cartridge achieved in situ sampling and enrichment of PPCPs. The NOP-SPE sampler effectively monitored 44 PPCPs with high recoveries (40–124 %), repeatability (RSDs <17.54 %), and reproducibility (RSDs <19.50 %). The sampling and sample pretreatment strategy of NOP-SPE was comparable with widely adopted active sampling methods followed by offline SPE pretreatment in terms of recoveries, repeatability, reproducibility, method detection limits, and method quantification limits in laboratory tests and wastewater effluent on-site tests. The advantages of the NOP-SPE sampler include: high efficiency, low cost, no need for external power, reduced sample pretreatment time, minimized PPCP degradation and adsorption during storage. Therefore, it provides a viable strategy for the sampling and pretreatment of micropollutants in aquatic environment. The NOP-SPE sampler can overcome the challenges associated with manpower and electrical power constraints in field composite sampling, thereby contributing importantly to water environment protection and management. • Development of a novel power-free in situ sampler for trace substances. • Comparing NOP-SPE samplers with traditional manual sampling and automated sampler. • Sampler performance investigated at a wastewater treatment plant. • The NOP-SPE sampler is capable of collecting data that reflect time-weighted average concentrations.