Quantification of amphetamines

Andersson et al. have recently proposed a direct injection LC-MS/MS method for the identification and quantification of amphetamine, methamphetamine, MDA, and MDMA in urine drug testing. The samples were prepared for analysis by fivefold dilution with ultra pure water [119]. A gradient elution was performed using two solvents 25 mM formic acid containing 1 % acetonitrile and 25 mM formic acid containing 90 % acetonitrile. Authors observed matrix effects, in terms of ion suppression, about 25-fold. This method was used for real sample analysis and... 

Andersson M, Gustavsson E, Stephanson N, Beck O (2008) Direct injection LC-MS/MS method for identification and quantification of amphetamine, methamphetamine, 3,4-methyl-enedioxyamphetamine and 3,4-methylenedioxymethamphetamine in urine drug testing. J ChromatogrB Analyt Technol Biomed Life Sci 861 22-28. 10.1016/j.jchromb.2007.11.025... 

Peters, F.T., Schaefer, S., Staack, R.F., Kraemer, T., Maurer, H.H. Screening for and validated quantification of amphetamines and of amphetamine- and piperazine-derived designer drugs in human blood plasma by gas chromatography/mass spektrometry. J. Mass Spectrom. 38, 659-676 (2003)... 

P Esseiva, E Lock, O Gueniat, MD Cole. Identification and quantification of amphetamine and analogues by capillary zone electrophoresis. Sci Justice 37 113-119, 1997. 

Miller El, Wylie FM, Oliver JS. Simultaneous detection and quantification of amphetamines, diazepam and its metabolites, cocaine and its metabolites, and opiates in hair by LC-ESI-MS-MS using a single extraction method. J Anal Toxicol 2008 32(7) 457-69. 

Al-Dirbashi O, Wada M, Kuroda N, Takahashi M, Nakashima K. 2000. Achiral and chiral quantification of methamphet-amine and amphetamine in human urine by semi-micro column high-performance liquid chromatography and fluorescence detection. J Forensic Sci 45(3) 708-714. 

QUANTIFICATION. The addition of the internal standard (10 yg) to the urine before extraction is necessary for the quantification procedures. Known amounts of amphetamine and diphenylamine in the range 0-5 yg are chromatographed and calibration curves are plotted for peak area (y axis) versus concentration (x axis). 

The detector response is greater for diphenylamine than for an equivalent amount of amphetamine. Over the 0-5.0 yg range, the ratio expressed as a percentage averaged 83%. Quantification is linear over the range used. 

To determine recovery, amounts of amphetamine and diphenyl-amine in the range 0-20 yg are added to normal urine and then extracted and assayed according to the procedure. Quantification is done and the mean percent recovery for amphetamine was 82% and for diphenylamine it was 83%. 

At the present time, it is possible to carry ont identification and quantification of a wide variety of drugs, ranging from those which are entirely herbal or fnngal in origin Cannabis and its prodncts), throngh those which are semisynthetic (cocaine and diamorphine), to those which are entirely synthetic (the amphetamines). A wide variety of techniqnes can be applied for their analysis and it is rare that an issue of sensitivity becomes apparent. In terms of dmg identification and quantification, the dmg analyst is in a particnlarly strong position. 

Cais, who coined the term metalloimmunoassay, prepared a series of organometallic markers (metallohaptens) with the potential for use in immunoassay. These are derivatives of steroids (estradiol, estriol), mood-altering drugs (amphetamine and cocaine) or medications (morphine and barbiturates), labeled with ferrocene, cobaltocenium and cymantrene [57-59]. He then assessed the use of a Sepharose 4B column to separate the free and bound fractions of the tracer and quantification of the tracer by atomic absorption spectrometry [58]. 

Cordero R, Paterson S (2007) Simultaneous quantification of opiates, amphetamines, cocaine and metabolites and diazepam and metabolite in a single hair sample using GC-MS. J Chromatogr B 850 423—431... 

Sources (1) Liau, A. S., et al. "Optimization of a simple method for the chiral separation of methamphetamine and related compounds in clandestine tablets and urine samples by beta-cyclodextrine modified capillary electrophoresis a complementary method to GC-MS." Forensic Science International, 134 2003,17-24. (2) Cheng, W.-C., et al. "Enantiomeric Separation of Methamphetamine and Related Analogs by Capillary Zone Electrophoresis Intelligence Study in Routine Methamphetamine Seizures." Journal of Forensic Sciences, 47 2002,1248-1252. (3) Al-Dirbashi, O., et al. "Achiral and Chiral Quantification of Methamphetamine and Amphetamine in Urine by Semi-micro Column High Performance Liquid Chromatography and Fluorescence Detection." Journal of Forensic Sciences, 45 2000,708-714. 

TABLE 14.2 Quantification Limit and Linearity for the Analysis of Amphetamines... 

Methods for identification of amphetamine and methamphetamine in nrine have been employed using GC/Fourier transform IR (GC/FTIR) spectroscopy (104) however these are not widely used. These methods have provided identification of the amphetamines and metabolites at the low picogram levels. Developments in cryogenic sample deposition for GC/FTlR spectroscopy have allowed the highly selective ability of IR spectroscopy to be used for identification and quantification of these drugs. 

Shin, H.S., and Donike, M. (1996) Stereospecific derivatization of amphetamines, phenol alkylamines, and hydroxyamines and quantification of the enantiomers by capillary GC/MS. Analytical Chemistry, 68, 3015-3020. 

Toxic impurities are those that have a significant undesirable biological activity even at low concentrations and require identification and quantification by specific tests. They may arise from the synthesis, preparation, or degradation of the drug. An example of a toxic impurity is amphetamine hydrochloride in phenylpropanolamine hydrochloride, which the USP limits to 0.001%. 

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