Detection of adulteration in acetonitrile

To address the increasing concern that acetonitrile may be intentionally adulterated to meet the shortfall in global supplies resulting from a downturn in its manufacturing, three analytical techniques were examined in this study. Gas Chromatography with Thermal Conductivity Detection (GC–TCD), Near Infrared (NIR) spectroscopy and Fourier Transform Infrared (FT-IR) spectroscopy were assessed for their ability to detect and quantify potential adulterants including water, alternative organic solvents, and by-products associated with the production of acetonitrile. The results of the assessment of the three techniques for acetonitrile adulteration testing are discussed.

► The GC–TCD method is capable of resolving all of the adulterants with excellent quantification and demonstrates good precision, accuracy and linearity at the ≥1% level of spiked adulterants.
► GC–TCD method provides relatively easy quantification of the foreign substance in acetonitrile. Furthermore, if mass spectrometry were used either in conjunction or as a substitute for TCD, identification of foreign substances not examined in this report could be readily achieved.
► NIR in combination with the Conformity Test algorithm is able to differentiate the adulterated samples from the unadulterated samples.
► FTIR was not able to detect all of the tested adulterants in acetonitrile and FTIR cannot provide quantitative measurement of the adulterants in acetonitrile.