posted on 2020-01-07, 16:42authored byBryan J. McCullough, Kirtan Patel, Ryan Francis, Peter Cain, David Douce, Kate Whyatt, Steve Bajic, Nicola Lumley, Chris Hopley
The
emergence of ambient ionization techniques and their combination
with smaller, cheaper mass spectrometers is beginning to make real
the possibility of mass spectrometry measurements being made routinely
outside of traditional laboratory settings. Here, we describe the
development of an atmospheric solids analysis probe (ASAP) source
for a commercially available miniaturized, single-quadrupole mass
spectrometer and subsequent modification of the instrument to allow
it to run as a deployable system; we further go on to describe the
application of this instrument to the identification of the contents
of drug seizures. For the drug seizure analysis, a small quantity
of the material (powder, tablet, resin, etc.) was dissolved in ethanol
and shaken to extract the analytes, the resulting solutions were then
sampled by dipping a sealed glass capillary into the solution prior
to analysis by ASAP–MS. Identification of the contents of the
seizures was carried out using a NIST searching approach utilizing
a bespoke spectral library containing 46 compounds representative
of those most commonly encountered in UK forensic laboratories. In
order to increase confidence in identification the library sample
and subsequent analyses were carried out using a four-channel acquisition
method; each channel in this method used a different cone voltage
(15, 30, 50, and 70 V) inducing differing levels of in-source fragmentation
in each channel; the match score across each channel was then used
for identification. Using this developed method, a set of 50 real-life
drug samples was analyzed with each of these being identified correctly
using the library searching method.