ABSTRACT
Because many therapeutic agents are contaminated by epimeric impurities or form epimers as a result of metabolism, analytical tools capable of determining epimers are increasingly in demand. This article is a proof-of-principle report of a novel DMS-MS/MS method to separate and simultaneously quantify epimers, taking PGF2 and its 8-epimer, 8--PGF2, as an example. Good accuracy and precision were achieved in the range of 10-500 ng/mL with a run time of only 1.5 min. Isopropanol as organic modifier facilitated a good combination of sensitivity and separation. The method is the first example of the quantitation of epimers without chromatographic separation.
ABSTRACT
Using a novel hybrid technology combined differential ion mobility spectrometry ( DMS) with drift time ion mobility spectrometry DMS-IMS2 , we detected the typical chemical warfare agent simulants dimethyl methylphosphonate ( DMMP ) and methyl salicylate ( MS) . With carrier gas 800 mL/min and DMS RF voltage 1100 V, the chemical warfare agents DMMP and MS could be detected and characterized by DMS-IMS2 under DIMS mode. In addition, DMS-IMS2 is capable to monitor positive and negative ions of DMMP and MS simultaneously, and provides the two-dimensional separation parameters DMS compensation voltage ( CV) and IMS drift time ( Td ) , which provides more information for the identification of two chemical warfare agents. DMS-IMS2 has potential application in on-site detection and instrument miniaturization due to its advantages including small size, low power consumption and rapid response time.