Open AccessSecondary electrospray ionization (SESI) of ambient vapors for explosive detection at concentrations below parts per trillion
Author(s) -
P. Martínez-Lozano,
Juan Rus,
Gonzalo Fernández de la Mora,
Marta Hernández,
Juan Fernández de la Mora
Publication year - 2009
Publication title -
journal of the american society for mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.961
H-Index - 127
eISSN - 1879-1123
pISSN - 1044-0305
DOI - 10.1016/j.jasms.2008.10.006
Subject(s) - chemistry , desorption electrospray ionization , extractive electrospray ionization , explosive material , electrospray ionization , ambient ionization , ionization , analytical chemistry (journal) , mass spectrometry , dart ion source , parts per notation , detection limit , electrospray , chemical ionization , ion , chromatography , sample preparation in mass spectrometry , electron ionization , organic chemistry
We determine the sensitivity of several commercial atmospheric pressure ionization mass spectrometers towards ambient vapors, ionized by contact with an electrospray of acidified or ammoniated solvent, a technique often referred to as secondary electrospray ionization (SESI). Although a record limit of detection of 0.2 x 10(-12) atmospheres (0.2 ppt) is found for explosives such as PETN and 0.4 ppt for TNT (without preconcentration), this still implies the need for some 10(8)-10(9) vapor molecules/s for positive identification of explosives. This extremely inefficient use of sample is partly due to low charging probability ( approximately 10(-4)), finite ion transmission, and counting probability in the mass spectrometer (1/10 in quadrupoles), and a variable combination of duty cycle and background noise responsible typically for a 10(3) factor loss of useful signal.