Providing quality assurance for blood gas analyzers using MIMS
About 15 years ago, someone called with the question, “Can you measure argon in water?”. At the time, dissolved Ar wasn’t (and still isn’t) a mainstream analysis, but we were in the early years of developing our MIMS for high precision dissolved gas analyses and the N2/Ar technique and we offered to help out this product laboratory at Bayer Corporation. This became a several year research collaboration which prompted significant advances in our MIMS instrument and method of calibration. We’re indebted to Bob and his colleagues for pushing us to tame our MIMS instrument and develop more reliable and precise results. The initial Ar measurements led to O2 and CO2 measurements, which became the basis of an FDA-approved method for validating pCO2 and pO2 in calibration solutions used in their blood gas analyzers. Though the technology passed from Bayer to Siemens in the intervening years, we have continued to provide the MIMS instrumentation for primary validation of their calibration solutions and this summer we delivered two new MIMS instruments to their expanding production facility.
Precise dissolved gas concentrations can only be obtained with both high precision standards and a MIMS configuration that provides highly stable and predictable signals for the standard. Our MIMS is unique in providing both of these features which translate to the precision of dissolved gas concentrations at a level of 0.1% as compared to 0.03% for N2/Ar or O2/Ar ratios. Our work with Bayer demonstrated that individual gas concentrations could be measured by MIMS at high precision, which is considerably more challenging than obtaining high precision gas ratios. This capability opens the door to new applications for multi-gas analysis, particularly in environmental science where high precision of gas concentrations may be required to distinguish small disequilibria. A prime example is with Ar concentration measurements to determine solubility disequilibria and physical processes. (See our Blog post “N2/Ar or N2 and Ar”)