The Application of Solid Phase Extraction in EPA Method 625 for Synthetic Wastewater and TCLP Leachate Samples
Oral Presentation
Prepared by X. Wang
UCT, 2731 Bartram Rd, Bristol, PA, 19007, United States
Contact Information: xwang@unitedchem.com; 215-781-9255
ABSTRACT
EPA method 625 was published many years ago for the analysis of base/neutrals and acids in municipal and industrial wastewater using liquid-liquid extraction (LLE) and GC/MS detection. This method has been updated recently by Lemuel Walker (Office of Science and Technology, US EPA, Washington DC) allowing for the use of solid phase extraction (SPE) as an alternative sample preparation technique as long as quality control (QC) data meet the method requirements. To verify that SPE offers comparable analytical performance to LLE, the Independent Laboratory Institute (ILI) has organized a working group that includes regulatory agencies, commercial SPE vendors, analytical testing laboratories and academia. This group compared SPE and LLE using the same blind samples; tests were conducted in three individual laboratories for each SPE product using the same matrices, such as ASTM synthetic wastewater and leachate from the toxicity characteristic leaching procedure (TCLP). The surrogate (or system monitoring compound) list has been expanded from the original six (all acidic or neutral) to seventeen compounds that are more representative of the total 625 compound list. The expanded list includes compounds such as n-nitrosodimethylamine-d6 for small polar compounds, and 4-chloroaniline-d4 for basic compounds. UCT is one of several SPE vendors that participated in this validation study; with its specially developed sorbents and SPE method, clean extracts, low method detection limits, and excellent recoveries (even for several compounds that usually result in low recoveries when using LLE, such as 2,4-dinitrophenol and benzidine) were obtained for over 100 target analytes tested in this study.
Oral Presentation
Prepared by X. Wang
UCT, 2731 Bartram Rd, Bristol, PA, 19007, United States
Contact Information: xwang@unitedchem.com; 215-781-9255
ABSTRACT
EPA method 625 was published many years ago for the analysis of base/neutrals and acids in municipal and industrial wastewater using liquid-liquid extraction (LLE) and GC/MS detection. This method has been updated recently by Lemuel Walker (Office of Science and Technology, US EPA, Washington DC) allowing for the use of solid phase extraction (SPE) as an alternative sample preparation technique as long as quality control (QC) data meet the method requirements. To verify that SPE offers comparable analytical performance to LLE, the Independent Laboratory Institute (ILI) has organized a working group that includes regulatory agencies, commercial SPE vendors, analytical testing laboratories and academia. This group compared SPE and LLE using the same blind samples; tests were conducted in three individual laboratories for each SPE product using the same matrices, such as ASTM synthetic wastewater and leachate from the toxicity characteristic leaching procedure (TCLP). The surrogate (or system monitoring compound) list has been expanded from the original six (all acidic or neutral) to seventeen compounds that are more representative of the total 625 compound list. The expanded list includes compounds such as n-nitrosodimethylamine-d6 for small polar compounds, and 4-chloroaniline-d4 for basic compounds. UCT is one of several SPE vendors that participated in this validation study; with its specially developed sorbents and SPE method, clean extracts, low method detection limits, and excellent recoveries (even for several compounds that usually result in low recoveries when using LLE, such as 2,4-dinitrophenol and benzidine) were obtained for over 100 target analytes tested in this study.
