Rapid analysis of N-methylpyrrolidine in cefepime with thermal desorption ion mobility spectrometry

N-methyl-pyrrolidine (NMP) a potential impurity in the cephalosporin antibiotic cefepime is analysed using a rapid thermal desorption – ion mobility spectrometry (TD-IMS) method. The thermal desorption approach is shown to be capable of rapidly extracting NMP from the cefepime at 80 °C without causing thermal degradation of the cefepime. The ion mobility method has an analysis time of 1 min and demonstrates good linearity over a range from 0.3–3.0 μg ml−1 of NMP, with limits of detection and quantification of 0.056 and 0.1875 μg ml−1 respectively. The developed method was applied to the analysis of a cefepime sample and determined that NMP was present in a cefepime sample at a level of 0.0376 % with a percentage relative standard deviation (n = 6) of 3.2 %. This was compared with a LC-UV method which was in close agreement measuring NMP at 0.0384 % in the cefepime sample with a percentage RSD (n = 6) of 5.7 %. These results show that the TD-IMS method gives comparable data to the established LC methods and demonstrates the potential of TD-IMS for rapid measurement of volatile compounds in pharmaceutical matrices.