Rapid label-free determination of ketamine in whole blood using secondary ion mass spectrometry

Rapid simultaneous determination of ketamine and midazolam in biological samples using ion mobility spectrometry combined by headspace solid-phase microextraction

Ketamine (Ket) and midazolam (Mdz) are among well-known anesthetic agents which frequently coadministered in surgical procedures and emergency department. Only a few reports have been published for the simultaneous analysis of these compounds. In the present study, we reported a simple, sensitive, and rapid method for simultaneous determination of Ket and Mdz based on headspace solid-phase microextraction coupled with ion mobility spectrometry (HS-SPME-IMS). Ion mobility spectrometer operated under positive mode of a corona discharge ionization source using ammonia as a dopant. The effective parameters on the extraction process consisting of pH of the sample, extraction temperature, extraction time, salt concentration were optimized. The calibration plots exhibited good linearity over the concentration ranges of 10-800 and 100-1500 µg L^-1 and detection limit of 8.9 and 52 µg L^-1 for Ket and Mdz respectively with correlation coefficients greater than 0.99. The relative standard deviation (RSD) for five replicate measurements was determined to be less than 8%. Finally, the applicability of the proposed method was tested in human plasma and serum samples. These tests showed that the matrix in serum samples interfere with midazolam determination but quantitative recoveries from 85 to 95 % were obtained for both drugs in the human plasma samples. The method herein provides simple and suitable approach while minimizing sample preparation and the overall complexity of the analysis in comparison to existing methodologies.

Targeted mass spectrometry of ketamine and its metabolites cis-6-hydroxynorketamine and norketamine in human blood serum

Ketamine (KET) was originally developed as an anesthetic agent but has also attracted attention for further clinical applications such as medical treatment of depression or pain. The use of KET induces dissociation and emergence delirium. Due to these effects, KET has a high potential for abuse. In order to investigate metabolization of KET or to confirm misuse of KET, highly sensitive analytical methods that cover KET and its metabolites are necessary. A new analytical approach for simultaneous analysis of KET and its metabolites cis-6-hydroxynorketamine (HNK) and norketamine (NK) was established. The compounds were extracted from human blood serum by ultrafiltration and solid phase extraction with subsequent vacuum evaporation. The compounds were analyzed by non-enantioselective ultra-high performance micro-flow liquid chromatography (Waters ACQUITY UPLC® M-Class HSS T3 column, 0.1% formic acid and acetonitrile with 0.1% formic acid, 14 µL/min flow rate) coupled with tandem mass spectrometry in positive scheduled multiple reaction monitoring mode. Validation parameters such as linearity, precision, recovery, accuracy, stability, limit of detection (LOD), and limit of quantification (LOQ) were proven. LOD for KET and NK was 0.08 ng/mL and LOQ were 0.5 ng/mL and 0.6 ng/mL, respectively. For HNK, LOD was 0.1 ng/mL and LOQ 0.8 ng/mL. The method was then successfully applied to quantify KET, HNK, and NK in blood serum samples from subjects who received KET intravenously. A novel method for the simultaneous analysis of KET, NK, and HNK was established. This new method could now be used for clinical trials investigating KET and its metabolites HNK and NK or for forensic analysis in order to confirm KET abuse.

Direct detection of morphine in human urine by surface-ionization mass spectrometry

Detection and analysis of drugs-of-abuse in biological fluids are the essential tasks for the law enforcement, forensic toxicology, doping research and social health. In this work, we developed a surface-ionization mass spectrometry method for direct detection of trace amount of morphine spiked in blank urine. The mass-spectrometric analysis of spiked samples was carried out without preliminary extraction and chromatographic separation. It was found out that the major fragment ions at m/z 144, 146 could be served as indicator lines of morphine spiked in blank urine. Limit of detection of morphine spiked in blank urine was 100 pg (50 ng/ml), and a linear range of calibration curve was more than two orders of magnitude. The spiked samples were also analyzed by gas chromatography-mass spectrometry without preliminary extraction and derivatization procedures. No morphine was found in the spiked samples. The experimental data show that the high selectivity of the surface ionization can be allowed to direct analysis of morphine spiked in blank urine without its preliminary extraction and chromatographic separation.

Time-of-flight secondary ion mass spectrometry analysis of chitosan-treated viscose fibres

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) was employed to analyse cellulose viscose fibres treated with different chitosan-based solutions. The analysis reports several new features in the TOF-SIMS spectra for systems with various forms of chitosan-treated surfaces. The characteristic positive ion TOF-SIMS signals for chitosan are reported at m/z 147.90, 207.07, and 221.09, and characteristic signals for trimethyl chitosan are present at m/z 58.03 and 102.09. Furthermore, new fragments were suggested to characterise acetylated chitosan molecules. The relative surface concentrations of different species were obtained based on the specific signal ratios (originating from a specific fragment and cellulose). SIMS imaging was then performed in order to investigate the surface distribution of chitosan, trimethyl chitosan, and Na-containing nanoparticles. In order to perform TOF-SIMS imaging, the above-mentioned characteristic signals were employed and m/z 22.99 was used for Na nanoparticles.