What are the advantages of SRI-MS?
While most of the astonishing advantages of PTR-MS are preserved when operating the instrument in SRI mode, several additional benefits arise:
Aldehydes and ketones, carboxylic acids and esters, carboxylic acids and alcohols and many more isomers can be separated (i.e. they will appear on different nominal masses) with NO+ as reagent ion.
Highest level of selectivity
Via fast switching of the reagent ions (for many reagent ions the switching process takes less than 10 s) different reaction pathways can be triggered. By comparing and interpreting these pathways substance identification becomes nearly unambiguous.
Virtually unlimited number of detectable substances
Ethylene, Acetylene, halocarbons and moreover CH4, CO, CO2, NO2, SO2 etc. cannot be ionized with proton tranfer from hydronium. All of these substances become detectable and quantifiable with an IONICON SRI-MS instrument using the appropriate reagent ion.
As IONICON PTR-MS instruments show a linear response over many orders of magnitude, quantification is made especially easy. For SRI-MS we recommend the use of a gas standard containing the compounds of interest in order to subsequently calculate absolute concentrations from the real sample.
Very high reagent ion yields and sensitivity
No matter if H3O+, O2+, NO+, NH4+, Kr+ or Xe+ is utilized as a reagent ion, IONICON instruments never require the use of a signal diminishing mass filter between the ion source and the drift tube. This results in outstandingly high reagent ion yields and subsequently to market-leading sensitivities and detection limits, IONICON is and has always been known for.
Learn more about the IONICON technologies here.