Retention behaviour of two biguanidines in liquid chromatography based on cyano stationary phase

A new way of improving the retention of biguanidines by means of cyano based stationary phase, followed by massspectrometry as detection approach in order to be applied to the determination of low levels of biguanidines in complex samples, such as biological ones. Two biguanidines were studied in this paper: N,N-dimethylbiguanidine and Nmethylbiguanidine. The retention study revealed an exponential functional dependence of the retention of target solutes on the mobile phase in accordance to a normal-phase mechanism: the retention time for both biguanidines increased with the increase of the organic modifier content (methanol, or acetonitrile).