Direct detection of the psychoactive substance MT‐45 in human tissue samples by probe electrospray ionization‐tandem mass spectrometry

Abstract

Analyses of drugs and poisons in tissue samples are essential in forensic toxicology and pharmacology. However, current procedures for tissue analysis are laborious and time-consuming. Therefore, we assessed the utility of a newly devised probe electrospray ionization (PESI) technique with tandem mass spectrometry (MS/MS) for easy, ultra-rapid drug detection in human tissue samples. Using this system, typical pretreatment procedures, such as solid-phase extraction, liquid-liquid extraction, deproteinization, or homogenization, can be avoided. Briefly, a tissue sample of 1-2 mm was supplemented with a solution of ethanol and 10 mmol/L ammonium formate, and measurements were obtained. We demonstrated the successful application of this method in a forensic case by detecting an opioid analgesic, MT-45, in all tissue samples (liver, kidney, lung, brain, and heart). We also detected oxidized metabolites of MT-45 in the liver. Since the analysis required only 0.5 minutes per sample, PESI-MS/MS is an ultra-rapid detection method. Furthermore, for a quantitative approach, the total analysis time for the combination of PESI-MS/MS with the quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction method (from instrument start-up to extraction and PESI-analysis) was within 8 minutes. MT-45 concentrations obtained by QuEChERS-PESI-MS/MS and liquid chromatography (LC) -MS/MS were similar for all tissue samples. PESI-MS/MS cannot be used to separate isobars/isomers (ie, compounds with the same m/z value), similar to other direct introduction techniques. Further studies are needed to validate the quantitation method. However, our results indicate that PESI-MS/MS is a potentially easy and rapid technique for the analysis of drugs and poisons in human tissue samples.

Molecularly Imprinted Polymer-Coated Probe Electrospray Ionization Mass Spectrometry Determines Phorbol Esters and Deoxyphorbol Metabolites in Jatropha curcas Leaves

“…The needle touches the sample for analyte extraction, and subsequently, the needle is positioned in front of the mass spectrometer inlet orifice. A high voltage is applied to the needle, and an electrolytic spray is formed, followed by the ion analysis by MS. PESI has already been employed for direct MS analysis of foods [17], psychoactive drugs [18], plants [19], metabolites from mouse liver [20], and brain [21], including detection of metabolites at subcellular levels [22].…”

Developments in high-resolution mass spectrometric analyses of new psychoactive substances

“…When the probe needle was brought into contact with the sample, a high voltage was applied to generate ions which could be introduced into the HRMS detector. The PESI-HRMS method presented was able to detect the presence of MT-45 in all tissue samples analysed, along with two potential hydroxylated metabolites with similar concentrations to conventional analyses (Usui et al 2018 ). While the nature of direct analysis techniques makes it difficult to separate compounds with the same precursor mass, due to the lack of a chromatographic separation step, the presented direct analysis methods demonstrate the potential for such techniques to be used as alternate rapid screening analysis approaches.…”

“…While most direct MS analysis techniques focus on screening for drugs prior to ingestion to reduce the potential effects from complex biological matrices, Usui et al ( 2018 ) presented a probe electrospray ionisation (PESI) method designed for the direct detection of MT-45 in human tissue. Various tissue samples were placed on dedicated plastic sample plates before being placed into the PESI source.…”

Endothelium-Independent Relaxation of Vascular Smooth Muscle Induced by Persimmon-Derived Polyphenol Phytocomplex in Rats

“…A Shimadzu 8045 triple quadrupole mass spectrometer with a probe electrospray ionization (PESI) ion source (Shimadzu, Kyoto, Japan) was used for the direct detection of catechin components. The samples were placed directly on a dedicated plastic sample plate and set on the PESI ion source [ 28 ]. The probe needle was lowered such that the needle tip touched the sample and then was raised to apply a high voltage for ionization.…”