Current Method Development Activities (Commercial Lab Perspective)
Oral Presentation
Prepared by A. Eaton, A. Haghani
Eurofins Eaton Analytical, 750 Royal Oaks Drive, Monrovia, CA, 91016, United States
Contact Information: [email protected]; 626-386-1125
ABSTRACT
Over the last 10 years, there has been a greatly increased demand for analysis of trace compounds that are too polar or insufficiently volatile for traditional GC-MS analyses. This trend was first demonstrated in USEPA’s second round of the Unregulated Contaminant Monitoring Rule (UCMR2) when EPA required the use of method 535 for acetanilide herbicide degradates. This prompted at least a few commercial labs to begin acquiring modern LC-MS-MS technology. At the same time with the increased interest in pharmaceuticals and personal care products in water at trace levels there was significant methods development occurring in the LC-MS-MS arena. Since the mid 2000s, there have been numerous LC-MS-MS methods developed both in house by laboratories such as ourselves and by USEPA. Most of the development in commercial labs has focused on issues of a) sensitivity; b) ruggedness via the use of isotope dilution whenever possible and c) data reduction challenges. In our own lab we have both worked as a second lab validator for many of the USEPA LC-MS-MS methods that have either been direct aqueous injection methods or typically off line SPE methods; and also worked on a number of on-line SPE methods, many of which have now become routine production techniques. These have included PPCPs, broad screen pesticide methods, and even individual analyte focused methods such acrylamide, bromate, and chlorate in complex matrices. While LC-MS-MS is not without its challenges in terms of matrix suppression or enhancement and the choice of proper mobile phases and columns to optimize separation, one of the biggest challenges has been the data reduction issue. We typically follow European guidelines as far as using multiple transitions to avoid false positives and rely heavily on stable isotopes when they are cost effective. Using high pressure liquid chromatography or UPLC it is possible to generate peaks for more than 100 analytes in < 20 minutes, but in a complex matrix such as a wastewater effluent the data reduction time can be 2-3 hours for a single run, without efficient software. We have recently been using the Thermo Trace Finder software to significantly cut the data reduction time in these complex matrices. The other item that is often overlooked by commercial labs in doing methods development is the issue of compound stability, so we typically do extensive preservation and holding time studies in conjunction with our methods development, particularly if looking for “new” analytes for which there are no existing standardized methods.
This presentation will review our experience in doing methods development, using several examples; an online SPE method for PPCPs and a method we recently finished validating for > 150 pesticides of various classes.
Oral Presentation
Prepared by A. Eaton, A. Haghani
Eurofins Eaton Analytical, 750 Royal Oaks Drive, Monrovia, CA, 91016, United States
Contact Information: [email protected]; 626-386-1125
ABSTRACT
Over the last 10 years, there has been a greatly increased demand for analysis of trace compounds that are too polar or insufficiently volatile for traditional GC-MS analyses. This trend was first demonstrated in USEPA’s second round of the Unregulated Contaminant Monitoring Rule (UCMR2) when EPA required the use of method 535 for acetanilide herbicide degradates. This prompted at least a few commercial labs to begin acquiring modern LC-MS-MS technology. At the same time with the increased interest in pharmaceuticals and personal care products in water at trace levels there was significant methods development occurring in the LC-MS-MS arena. Since the mid 2000s, there have been numerous LC-MS-MS methods developed both in house by laboratories such as ourselves and by USEPA. Most of the development in commercial labs has focused on issues of a) sensitivity; b) ruggedness via the use of isotope dilution whenever possible and c) data reduction challenges. In our own lab we have both worked as a second lab validator for many of the USEPA LC-MS-MS methods that have either been direct aqueous injection methods or typically off line SPE methods; and also worked on a number of on-line SPE methods, many of which have now become routine production techniques. These have included PPCPs, broad screen pesticide methods, and even individual analyte focused methods such acrylamide, bromate, and chlorate in complex matrices. While LC-MS-MS is not without its challenges in terms of matrix suppression or enhancement and the choice of proper mobile phases and columns to optimize separation, one of the biggest challenges has been the data reduction issue. We typically follow European guidelines as far as using multiple transitions to avoid false positives and rely heavily on stable isotopes when they are cost effective. Using high pressure liquid chromatography or UPLC it is possible to generate peaks for more than 100 analytes in < 20 minutes, but in a complex matrix such as a wastewater effluent the data reduction time can be 2-3 hours for a single run, without efficient software. We have recently been using the Thermo Trace Finder software to significantly cut the data reduction time in these complex matrices. The other item that is often overlooked by commercial labs in doing methods development is the issue of compound stability, so we typically do extensive preservation and holding time studies in conjunction with our methods development, particularly if looking for “new” analytes for which there are no existing standardized methods.
This presentation will review our experience in doing methods development, using several examples; an online SPE method for PPCPs and a method we recently finished validating for > 150 pesticides of various classes.
