Adoption of APGC-MS/MS

Several regulatory agencies, including the USEPA, have recognized tandem quadrupole mass spectrometry (MS/MS) as an acceptable alternative to traditional high-resolution magnetic sector mass spectrometry for a number of different regulatory methods. These include USEPA Method 1613, as well as several EU methods (EU644-2017 and EU771-2017, for example). The Waters APGC TQ-XS has been validated by several laboratories and shown to have superior detection limits to both magnetic sector instruments as well as the electron ionization MS/MS systems offered by other manufacturers.

This recent recognition frees laboratories to successfully adopt the Waters Xevo TQ-XS APGC-MS/MS platform for the identification and quantification of polychloro-dioxin/furans in a wide variety of sample matrices.

Ultimate sensitivity

APGC ionization is softer than that of EI giving a more abundant precursor ion. Additionally, ion throughput on the tandem quadrupole system is higher than on the magnetic sector systems, yielding a gain in sensitivity. When APGC is coupled with the Xevo TQ-XS, the system is the most sensitive GC-MS/MS system commercially available allowing the most difficult regulations to be met with ease.

Exceed the performance of magnetic sector instruments

Improved sensitivity is only useful if method detection limits (MDL’s) are also improved, which they are with the APGC TQ-XS. Given the wide dynamic range, detector sensitivity and robust ion source design, MDL’s are improved relative to HRMS instruments.

In the figure, the blue bars are MDL values reported from an MDL validation data set on the APGC TQ-XS. The red bars represent the MDL’s on the HRMS system.

Improvements in robustness with APGC-MS/MS

The unique source design and StepWave technology in the Xevo TQ-XS with APGC offers high levels of matrix tolerance and gives excellent injection-to-injection repeatability. Less sample volume is needed which minimizes matrix effects and contamination on the system, in turn reducing the need for time-consuming purification steps and increasing uptime respectively.

Because the sensitivity is great enough, split injections can be used while still maintaining regulatory compliance thus exposing the column and mass spectrometer to lower levels of contamination. This results in a considerable improvement in robustness; something that other instruments are not capable of achieving.

Proven commercial success

Waters has partnered with several organizations to deliver advanced MS/MS technologies for dioxins analysis. Most recently, Waters working alongside with SGS AXYS validated an alternative test procedure for PCDD/PCDF analysis using APGC-MS/MS. This technology was successfully adapted to Method 1613B protocols and is referenced as the SGS AXYS Method 16130.

“This is one of my favorite instruments, it’s highly sensitive and selective due to the soft ionization with APGC. It is easy to operate, and low-maintenance compared to the magnetic sector, which is a big benefit to routine analysis. Also, I am able to switch between methods without any difficulty” Mr. Xinhui Xie, Senior Instrument Chemist at SGS AXYS.

Adopting new technologies to evolve dioxins analysis

Professor Bert van Bavel, Chief Scientist, Norwegian Institute for Water Research has assessed the use of both our Ion mobility MS and APGC-MS/MS for exploring dioxins in more detail.

“The first time we discovered the extreme sensitivity of the APGC ion source, it was really an eye opener for me and made it the perfect replacement for high resolution magnetic sector instruments for the analysis of dioxins. Now user friendly bench top instrumentation is available for trace analysis (much to the delight of my students and staff).”