Quantification of Free and Total Carnitine in Serum Using Liquid Chromatography Tandem Mass Spectrometry.

L-carnitine is a crucial component for transporting long-chained fatty acids from the cytosol into the mitochondrial matrix for fatty acid oxidation. During this process, carnitine forms numerous acylcarnitines before being recycled into the cytosol. Abnormal levels of free carnitine, total carnitine, and acylcarnitines in serum can be indicative of a metabolic disorder before symptoms are present. A liquid chromatography tandem mass spectrometry (LC-MS/MS) method is described for the determination of free and total carnitine in serum. To measure total carnitine, samples are spiked with deuterated carnitine (internal standard) and hydrolyzed with potassium hydroxide to convert acylcarnitines to carnitine. The reaction is quenched by the addition of hydrochloric acid. Carnitine is extracted via a methanolic protein precipitation. The solution is then injected on LC-MS/MS for analysis to determine the carnitine concentration using multiple-reaction monitoring.

A fatality involving 1,3-propanediol and its implications in measurement of other glycols.

The decomposed body of a 45-year-old female was found, face down, in a mobile home, along with a suicide note and two antifreeze containers. Analysis of the body fluid collected from the decedent showed the presence of 58 mg/dL ethanol, but suspected ethylene glycol was not found in the sample. However, an unusually large peak of internal standard, 1,3-propanediol, was found in the sample. Gas chromatography-mass spectrometry analysis confirmed the presence of 1,3-propanediol in the sample. Using gas chromatography-flame-ionization detection, the concentration of 1,3-propanediol was determined to be 445 mg/dL. To our knowledge, this is the first report involving 1,3-propanediol as the cause of death. The study also highlights the importance for the close scrutiny of data, as 1,3-propanediol is a frequently used internal standard for the assay of glycols.

Analysis of U-47700, a Novel Synthetic Opioid, in Human Urine by LC-MS-MS and LC-QToF.

The illicit drug market has rapidly evolved from synthetic cannabinoids to cathinone derivatives and now a new emerging threat of synthetic opioids. These compounds were mostly developed by pharmaceutical companies during drug discovery. The new psychoactive substances are not routinely covered in drug screening and may go undetected. Recently fentanyl analogous, AH-7921, MT-45 and now U-47700 have been encountered in clinical and forensic casework. U-47700 is gaining popularity on drug user forms as a legal alternative to heroin. It is a µ-receptor agonist that is part of the trans-1-2-diamine opioid analgesic drug class developed by The Upjohn Company in an attempt to develop a non-addicting analgesic. A LC-MS-MS method was developed and validated to detect and quantify U-47700. Additional analysis was conducted with an LC-QToF to identify the presence of the parent drug and metabolites. A total of four cases have been evaluated by the LC-MS-MS methodology which has an analytical range of 1-1,250 ng/mL and limit of detection of 1 ng/mL. The concentration of U-47700 in urine specimens ranged from below the limit of quantification to 224 ng/mL. The ToF analysis detected the presence of suspected phase I demethylated metabolites that may assist future analysis of this compound. The prevalence of designer opioids in casework highlights the importance of analysis for new psychoactive substances. Traditional opiates/opioids were not detected in the presented cases, but the available case histories revealed an opioid toxidrome. These findings suggest that U-47700 drug may cause significant morbidity and mortality within the United States as an emerging drug threat.

Simultaneous determination of cyclosporine, sirolimus, and tacrolimus in whole blood using liquid chromatography-tandem mass spectrometry.

A multiple reaction monitoring, positive ionization electrospray, liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is described for the simultaneous quantification of cyclosporine, sirolimus, and tacrolimus in human whole blood. Proteins in the samples are precipitated with a mixture of methanol and zinc sulfate. The supernatant is injected into the LC-MS/MS for analysis. Chromatography involves the use of a C18 column and ammonium acetate/water/methanol-containing mobile phases. The MS/MS is operated in positive ion electrospray mode. Quantification is achieved by comparing peak area ratios of MRMs of analytes and internal standards with that of calibrators. Calibration curves are constructed from peak area ratios of MRMs of calibrators and internal standards versus concentrations. MRMs used are ascomycin (m/z 809.5 → 756.5), cyclosporine A (m/z 1,219.9 → 1,203.1), cyclosporine D (m/z 1,234.0 → 1,217.0), sirolimus (m/z 931.6 → 864.5), and tacrolimus (m/z 821.5 → 768.4).

Three fatal intoxications due to methylone.

We present three fatal intoxications of methylone, a cathinone derivative. Blood was analyzed with a routine alkaline liquid-liquid extraction and analyzed by gas chromatography coupled with a mass spectrometer (GC-MS). Methylone was identified by a full scan mass spectral comparison to an analytical standard of methylone. For a definitive and conclusive confirmation and quantitation, methylone was also derivatized with heptafluorobutyric anhydride and analyzed by GC-MS. In all three fatalities, the deceased exhibited seizure-like activity and elevated body temperatures (103.9, 105.9 and 107°F) before death. Two of the three cases also exhibited metabolic acidosis. One of the three cases had prolonged treatment and hospitalization before death with symptoms similar to sympathomimetic toxicity, including metabolic acidosis, rhabdomyolysis, acute renal failure and disseminated intravascular coagulation. The laboratory results for this patient over the 24 h period of hospitalization were significant for increased lactate, liver transaminases, creatinine, myoglobin, creatine kinase and clotting times, and decreased pH, glucose and calcium. Peripheral blood methylone concentrations in the three fatal cases were 0.84, 3.3 and 0.56 mg/L. In conlusion, peripheral blood methylone concentrations in excess of 0.5 mg/L may result in death due to its toxic properties, which can include elevated body temperature and other sympathomimetic-like symptoms.

Quantitation of total 11-nor-9-carboxy-delta 9-tetrahydrocannabinol in urine and blood using gas chromatography-mass spectrometry (GC-MS).

Marijuana, which is made from crushing the leaves, flowers, and sometimes the stems of the plant Cannabis sativa, contains more than 30 cannabinoids. The major psychoactive cannabinoid is delta-9-tetrahydrocannabinol (THC). The major metabolite of THC, 11-nor-delta 9-carboxy-tetrahydrocannabionol (THC-COOH), is excreted in the urine primarily as a glucuronide conjugate and is commonly analyzed in biological specimens for detecting marijuana usage. The procedure described here involves the addition of deuterated internal standard THC-COOH-d9 into the sample followed by hydrolysis of conjugated THC-COOH by alkali. THC-COOH is extracted from urine or blood using liquid-liquid extraction followed by preparation of its trimethylsilyl derivatives. The analysis of derivatized THC-COOH is performed using gas-chromatography/mass spectrometry (GC/MS). Quantification of the drug in a sample is achieved by comparing the responses of the unknown sample to the responses of the calibrators using selected ion monitoring.