Negative atmospheric pressure chemical ionisation of NO 2 by O 2 − ·CO 2 ·(H 2 O) n studied by ion mobility spectrometry

In this study, negative polarity atmospheric pressure chemical ionisation-ion mobility spectrometry (APCI-IMS) was applied to study ionisation of NO 2 by O 2 − ·CO 2 ·(H 2 O) n reactant ions (RI) generated in the corona discharge ionisation source. The electron transfer reaction between RI and NO 2 resulted in the formation of NO 2 − .(H 2 O) n ions (drift gas temperature of 373 K). These ions were detected using IMS (reduced ion mobility of 2.46 cm 2 V −1 s −1 ) and IMS combined with time-of-flight mass spectrometer (IMS-MS) technique (m/z 46, 64, 82). The kinetics of the electron transfer reaction between O 2 − ·CO 2 ·(H 2 O) 0,1 and NO 2 was studied using IMS technique and rate coefficient of 0.88(± 0.20) × 10 −10 cm 3 s −1 was determined. The limit of detection (LOD) for NO 2 by IMS achieved value of 200 ppb v and the linear response range was in the range 0.05–7 ppm v . The sensitivity of the method was comparable with the electrochemical sensors; however, the present method has better selectivity and faster response time and it has the potential for further improvements. Graphic abstract Negative polarity atmospheric pressure chemical ionisation-ion mobility spectrometry (APCI-IMS) was used to study ionisation of NO 2 by O2 − ·CO 2 ·(H 2 O) n reactant ions. The ionisation rate coefficient was determined and new method of NO 2 detection was suggested