使用在线样品前处理LC-MS/MS技术定量分析ng/L级水中EPA1694药品和个人护理产品

前言：

　　There is growing environmental concern regarding the health impact of trace levels of pharmaceuticals and personal care products (PPCPs) in water resources. In response to this concern, the U.S. Environmental Protection Agency (EPA) recently published Method 1694, which determines dozens of PPCPs in water, soil, sediment, and biosolids by high performance liquid chromatography combined with tandem mass spectrometry (HPLC-MS/MS).1 The method, which is yet to be promulgated, uses solid phase extraction (SPE) of water samples followed by HPLC-MS/MS analysis using a single transition for each compound to achieve low nanogram/liter (ng/L) limits of quantitation (LOQs).

　　The target analytes in the EPA method are divided into four groups, with each group representing one HPLC-MS/MS run. Three of the groups are extracted under acidic conditions; the fourth is extracted under basic conditions. These SPE methods can use up to 1 L of sample. Although not sample limited, the storage of large bottles of water requires a great deal of refrigeration space. In addition, manual SPE of 1 L of sample requires several hours of preparation.

　　One of the opportunities in the analysis of PPCPs in water is to reduce the time required for sample preparation and analysis while maintaining the required sensitivity at the ng/L level and the selectivity to positively identify the analyte of interest. We describe a method for online sample preparation and analysis using the Thermo Scientific EQuan system. This method couples a fast HPLC system with two LC columns – one for pre-concentration of the sample, the second for the analytical analysis – and an LC-MS/MS instrument. Instead of processing 1 L of water by the manual, timeconsuming process of SPE described in EPA Method 1694, this alternative approach incorporates online sample preparation in series with LC-MS/MS using smaller volumes of water (0.5-20 mL) to achieve ng/L quantitation limits.

仪器：

Thermo Scientific TSQ Quantum mass spectrometer

结论：

　　The current EPA Method 1694 describes three different LC methods for PPCPs from Groups 1, 2, and 4, which are amenable to positive ESI-MS/MS. To simplify the method and reduce total analysis time, a single 10-minute LC-MS/MS method was developed on the EQuan system including compounds from additional pharmaceutical classes not included in the EPA method, such as beta-blockers and benzodiazepines.

　　The EQuan system significantly reduced sample preparation and analysis time while providing quantification of PPCPs in water at low ng/L levels. Online sample preparation of the water samples eliminated the need to use two different offline SPE methods on 1 L of water. This reduced the total analysis time from hours to minutes. The sensitivity of the TSQ Vantage mass spectrometer, using time-dependent SRMs to maximize detector duty cycle, provided low- or sub-ng/L limits of quantitation for the targeted PPCPs in water.