EnviroMail 19 Canada Trace GC/MS/MS 100 mL OC Pesticide Method Raises the Bar for Data Quality

ALS Environmental Canada is introducing a new Organochlorine Pesticide (OCP) test method for waters, using state-of-the-art GC/MS/MS triple quadrupole instrumentation to achieve trace level detection limits with near-zero chance of false positives, using 100 mL sample bottles. This new method raises the bar for data quality over traditional test methods that use either single quadrupole GC/MS or GC/ECD (Electron Capture Detection).

The unmatched sensitivity of our optimized GC/MS/MS triple quad method easily meets the lowest Canadian standards and guidelines for OCPs in water without the need for large 500 mL or 1 L sample volumes, which further advances the ALS commitment to sample size reduction to support faster and easier sample collection in the field with less potential for strain injuries to samplers.

ALS announced data quality and sample size reduction improvements to our OCP water methods in June 2019 with EnviroMail 14, when we introduced our OCP method for routine Limits of Reporting (LORs) using 100 mL sample bottles by traditional single quadrupole GC/MS. Our routine single quad method remains suitable for most common regulatory requirements and for most water samples, but our new GC/MS/MS method achieves detection limits up to 10 times lower, meeting the lowest of Canadian water quality standards and guidelines using the same 100 mL sample size as our routine method, while introducing significant new data quality benefits.

 

What is Triple Quad GC/MS/MS?

Both GC/MS and GC/MS/MS use gas chromatography to separate organic substances in time using a capillary chromatographic column interfaced to a mass spectrometric (MS) detector. Both techniques use an electron beam to ionize and fragment organic molecules as they elute from the GC column, with detection of mass-specific molecular fragments. But with GC/MS/MS, a technique called Multiple Reaction Monitoring (MRM) provides far greater selectivity and sensitivity. With MRM, a precursor ion is isolated in the first stage of the MS, which is then further fragmented in a collision cell (2^nd stage), with detection of unique “daughter” ions in the third stage of the spectrometer. GC/MS/MS eliminates most interferences that can occur with GC/MS because it only detects substances that can be ionized to produce the correct precursor ion, and where that precursor ion can be further fragmented to the correct secondary ion. Detection of these highly unique MRM “transitions” virtually guarantees the correct identification and accurate quantitation of each targeted analyte.