Rapid detection of drugs in biofluids using atmospheric pressure chemi/chemical ionization mass spectrometry

Abstract

We have demonstrated that, with simple pH adjustment, volatile drugs such as methamphetamine, amphetamine, 3,4-methylenedioxymethamphetamine (MDMA), ketamine, and valproic acid could be analyzed rapidly from raw biofluid samples (e.g. urine and serum) without dilution, or extraction, using atmospheric pressure ionization. The ion source was a variant type of atmospheric pressure chemical ionization (APCI) that used a dielectric barrier discharge (DBD) to generate the metastable helium gas and reagent ions. The sample solution was loaded in a disposable glass pipette, and the volatile compounds were purged by nitrogen gas to be reacted with the metastable helium gas. The electrodes of the DBD were arranged in such a way that the generated glow discharge was confined within the discharge tube and was not exposed to the analytes. A needle held at 100-500 V was placed between the ion-sampling orifice and the discharge tube to guide the analyte ions into the mass spectrometer. After pH adjustment of the biofluid sample, the amphiphilic drugs were in the form of a water-insoluble oil, which could be concentrated on the liquid surface. By gentle heating of the sample to increase the evaporation rate, rapid and sensitive detection of these drugs in raw urine and serum samples could be achieved in less than 2 min for each sample.

Determination of Illicit Drugs in Urine and Plasma by Micro-SPE Followed by HPLC–MS/MS

“…Urine has been the sample of choice for screening and identification of unknown drugs because the concentrations of these compounds are relatively high in this matrix [9][10][11][12]. Compared to plasma the correlation concentrationeffect is lost, but the time window is wider [13,14].…”

Fast screening of illicit drugs in beverages and biological fluids by direct coupling of thin film microextraction to dielectric barrier discharge ionization-mass spectrometry

“…Compared to other direct approaches where no sample pretreatment is performed, 18,19,26 the use of TFME as a fast and simple technique for liquid sample cleanup/up-concentration is very practical, because it minimizes the amount of interfering compounds ionized together with the analytes of interest (with possible suppression effects) and results in lower LODs due to the pre-concentration provided by the thin film. Although waiving the sample preparation completely would reduce the analysis time to just a few seconds per sample, it appears necessary to perform at least a simple sample pretreatment in order to be able to analyze complex matrices.…”

Towards Practical Endoscopic Mass Spectrometry

“…[7][8][9][10][11][12] Ambient MS or ambient ionization MS can be performed by replacing the original ion source of a commercial mass spectrometer with a custom-made electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI) variant. [13][14][15] To maximize the ion transmission to the vacuum of the mass spectrometer, the ionization is usually performed in close proximity to the ion inlet. To handle a large size sample such as living animals, the ionization has to be performed, say, at more than 1 m away from the MS instrument, and the remotely generated ions have to be transported back to the ion inlet using extended ion transported tube.…”