A convenient derivatization method for gas chromatography/mass spectrometric determination of phenmetrazine in urine using 2,2,2-trichloroethyl chloroformate.

Phenmetrazine is a central nervous system stimulant currently used as an anorectic agent. The drug is abused and is reported to cause death from overdose. We describe a new derivatization method for phenmetrazine using 2,2,2-trichloroethyl chloroformate. Quantitation of urinary phenmetrazine can be easily achieved by using N-propylamphetamine as an internal standard. The phenmetrazine 2,2,2-trichloroethyl carbamate showed a molecular ion isotope cluster at m/z 351, 353, 355, and 357 (isotope effect of three chlorine atoms in the derivatized molecule) and other peaks at m/z 247, 245, 204, 114, and 70 in the electron ionization mass spectrometry, thus aiding in unambiguous identification. The underivatized phenmetrazine showed a relatively weaker molecular ion at m/z 177 and a base peak at m/z 71. The N-propylamphetamine 2,2,2-trichloroethyl carbamate (internal standard) showed a very weak molecular ion at m/z 351 and a base peak at m/z 260. Another strong characteristic peak at m/z 91 was also observed. The retention time of derivatized phenmetrazine (9.5 min) was substantially longer than the retention time of the underivatized molecule (2.5 min). Moreover, underivatized phenmetrazine showed poor peak shape (substantial tailing) while derivatized phenmetrazine had excellent chromatographic property. The within-run and between-run precisions of the assay were 1.9% and 3.2% at a urinary phenmetrazine concentration of 20 micrograms/mL. The assay was linear for urinary phenmetrazine concentration of 1 microgram/mL to 100 micrograms/mL with a detection limit of 0.5 microgram/mL.

Gas chromatography-electron ionization and chemical ionization mass spectrometric analysis of urinary phenmetrazine after derivatization with 4-carbethoxyhexafluorobutyryl chloride--a new derivative.

Phenmetrazine is a central nervous system stimulant currently used as an anorectic agent. The drug is abused and is reported to cause death from overdose. We describe a new derivatization method for phenmetrazine using 4-carbethoxyhexafluorobutyryl chloride. Quantitation of urinary phenmetrazine can be easily achieved by using N-ethyl amphetamine as an internal standard. The electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of phenmetrazine showed a molecular ion at m/z 427 and a base peak at m/z 70. In the methane chemical ionization mass spectrum, the base peak was observed at m/z 428 (protonated molecular ion). In the electron ionization mass spectrum of 4-carbethoxyhexafluorobutyryl derivative of the internal standard, N-ethyl amphetamine we did not observe a molecular ion. However, in the chemical ionization mass spectrum, the protonated molecular ion at m/z 414 was the base peak. The retention time of derivatized phenmetrazine (8.4 min) was substantially longer than the retention time of the underivatized molecule. Moreover, underivatized phenmetrazine showed poor peak shape (substantial tailing) while derivatized phenmetrazine had excellent chromatographic properties. The within-run and between-run precisions of the assay were 2.6% and 3.1% respectively at a urinary phenmetrazine concentration of 10 micrograms/mL. The assay was linear for urinary phenmetrazine concentration of 1 to 100 micrograms/mL with a detection limit of 0.2 microgram/mL.

Determination of phenmetrazine in urine by gas chromatography-mass spectrometry after liquid-liquid extraction and derivatization with perfluorooctanoyl chloride.

Phenmetrazine is a central nervous system stimulant and is currently used as an anorectic agent. The drug is abused and reported to cause death from overdose. We describe a liquid-liquid extraction protocol for phenmetrazine from urine using 1-chlorobutane and subsequent derivatization using perfluorooctanoyl chloride for gas chromatography-mass spectrometric confirmation. Quantitation of urinary phenmetrazine can be easily achieved by using N-propylamphetamine as an internal standard. The perfluorooctanoyl derivative of phenmetrazine showed a weak molecular ion at m/z 573 and a characteristic strong peak at m/z 467 in the electron ionization mass spectrometry thus aiding unambiguous identification. The perfluorooctanoyl derivative of the internal standard did not show any molecular ion, but showed strong characteristic peaks at m/z 482 and 440. The within run and between run precisions of the assay were 1.7% and 3.2% at a urinary phenmetrazine concentration of 20 microgram/mL. The within run and between run precisions were higher (9.4% and 10.8%) at a urinary phenmetrazine concentration of 1.0 microgram/mL, which was very close to the detection limit of the assay. The assay was linear for urinary phenmetrazine concentration of 1 to 100 micrograms/mL with a detection limit of 0.5 microgram/mL.

Determination of Phenmetrazine in urine by gas chromatography-mass spectrometry.

A sensitive and simple gas chromatographic--mass spectrometric method is described for the determination of the central nervous system (CNS) stimulant phenmetrazine in urine. The extraction and derivatization were combined into a single step with isooctane and methyl chloroformate. The limit of quantitation was 0.05 micrograms/mliters urine, and the method was linear up to 100 micrograms/mliters. The coefficients of variation (CV) for within-day runs were 1.2% and 2.4% (n = 5) for two controls containing 1.0 micrograms/mliters and 50 micrograms/mliters, respectively. During a six-month period, the same controls showed CVs of 9.1% and 8.7%, respectively (n = 40), indicating a somewhat lower between-run precision. Phenmetrazine was present in 83 out of 3000 urine samples that were screened for CNS stimulants during this period, and the concentrations ranged from 0.5-370 micrograms/mliters.

Simultaneous determination of morazone and phenmetrazine in rat plasma and urine using an on-column injection technique with fused-silica capillary column gas chromatography.

The simultaneous determination of morazone and its major metabolite, phenmetrazine, using an on-column injection technique with fused-silica capillary column gas chromatography is described. The on-column injection technique prevents the decomposition of morazone. The limit of quantitation in 0.1 mL of rat plasma for morazone and phenmetrazine is 5 ng/mL and that in 1.0 mL of rat urine is 1 ng/mL. The within run precisions (%CV) at the concentration of 0.5 micrograms/mL are 3.27% for morazone and 3.09% for phenmetrazine.

[Investigations of the decomposition and detection of morazone by thin-layer- and gas-liquid-chromatography]. / Dünnschicht- und gaschromatographische Untersuchungen zum Nachweis und zur Stabilität des Morazons

Three decomposition products of Morazone (ingredient of the pharmaceutical preparation Rosimon-Neu) were observed following heat treatment in acid medium (hydrochloric or tartaric acid). These products were isolated by TLC and identified as bis-antipyryl-methane, phenmetrazine and 4-hydroxymethyl-antipyrine by mass spectrometry and IR-spectroscopy and 1H-nuclear magnetic resonance. Morazone and the metabolite phenmetrazine may be extracted from alkaline urine using chloroform, however acid hydrolysis (pH 1) of the urine before alkaline extraction will improve the sensitivity of detection of morazone by producing the metabolite phenmetrazine in addition to bis-antipyrylmethane. The metabolite 4-hydroxymethyl-antipyrine is barely detectable by TLC from alkaline extraction of urine.