Detection of explosive-related compounds by laser photoionization time-of-flight mass spectrometry

Ultrasensitive detection of explosives and chemical warfare agents by low-pressure photoionization mass spectrometry

“…The LOD was 4 pptv (2s), i.e., 0.2 pg. In previous studies, the LOD of NB ranged from 17 to 24 ppbv (2s) by GC/ PI-MS, [6] while the LOD was only 20 ppbv (3s) by sole PI-MS [22]. The LOD was improved by 4 orders of magnitude using the present technique as compared to the two methods abovementioned.…”

“…The LOD of the instrument towards 2,4-DNT was ultimately calculated to be 30 pptv (2.4 pg). In previous studies, the LOD of gas chromatography/ PI-MS towards 2,4-DNT was $ 40 ppbv (2s), [6] and the LOD of sole PI-MS towards 2,4-DNT was 40 ppbv (3s) [22]. The LOD obtained using this technique was improved by 3 orders of magnitude as compared to the previous reports.…”

“…However, this study indicates that LPPI will open new opportunities for the sensitive detection of explosives and chemical warfare agents. 1 2,4-DNT (2,4-dinitrotoluene) 182 Gas chromatograph/ PI-MS: [6] $ 40 ppbv(2s) 30 pptv, i.e., 2.4 pg PI-MS: [22] 40 ppbv (3s) 2 NT (nitrotoluene) 137 --0.5 pptv, i.e., 0.03 pg 3 NB (nitrobenzene) 123 Gas chromatograph/ PI-MS: [6] 17-24 ppbv (2s) 4 pptv, i.e., 0.22 pg PI-MS: [22] 20 ppbv (3s) 4 DMMP (dimethyl methyl Phosphonate) 124 Thermal desorption-PI-MS: [20] 750 ng (3s) 1 pptv, i.e., 0.06 pg miniature PI-MS: [18] 10-100 ppbv (3s) …”

“…Developments in photoionization (PI) technologies [17][18][19][20][21][22] have indicated that PI mass spectrometry (PI-MS) could be a viable alternative to IMS or PTR-MS. PI is a traditional analytical method [19]. Previously, it was limited to high vacuum conditions, where nascent ions were free from collisions.…”

“…Based on the pressure in the PI region, traditional PI is known as vacuum PI. Vacuum PI has been used widely and several pioneering reports have illustrated its viability in the detection of TAs; however, the LOD of vacuum PI is only at the ten-ppbv level [6,18,22]. Atmospheric pressure PI (APPI) is a relatively new technique employed under ambient pressure, which mainly yields ions via electron attachments and molecule/ion reactions.…”