The triple quadrupole MS provides a higher level of selectivity and is best suited to analyses where the highest sensitivity is required. This is often the case when quantitating pesticides in food or environmental contaminants. GC-MS/MS systems are typically operated in selective reaction monitoring (SRM) mode. The high selectivity of the SRM helps reduce interferences from background ions and produce a high signal-to-noise for excellent detection capability. GCMS is able to separate complex mixtures, quantify analytes, identify unknown peaks and determine trace levels of contamination.