Derivatization amphetamine

Is it possible to explain the origins of the fragments observed in the mass spectrum of amphetamine derivatized with oarbon disulfide (see Figure 2.4(c)) ... 

Table 2.3 GC operating conditions and parameters suitable for the analysis of amphetamine derivatized with carbon disulfide...

Figure 2.4 GC-MS data obtained for the NCS derivatives of standard and street samples of amphetamine (a) gas chromatogram of standard amphetamine derivatized with CS2 585 s) (b) gas chromatogram of a street sample of amphetamine derivatized with CS2 (fr (amphetamine), 585 s fr (caffeine), 845 s) (c) mass spectrum of the NCS derivative of standard amphetamine (d) mass spectrum of the NCS derivative of amphetamine in a street sample.

Derivatization of primary and secondary amines using 9-fluorenylmethyl chloroformate to form a nonpolar, uv-absorbing derivative has been reported (90,91). Amphetamine and catecholamine were used as probes to evaluate this procedure. The derivatives were well behaved and allowed separation in a short time. 

Santagati and associates (2002) reported a method for the determination of amphetamine and one of its metabolites, 4-hydroxynorephedrine by RP-HPLC with precolumn derivatization and amperometric electrochemical detection. The derivatization was performed with 2,5-dihydroxybenzaldehyde as the electroactive reagent. The compounds were separated on a Hypersil ODS RP-18. The detector oxidation was set at +0.6 volts. 

Several other methods have been published using RP-HPLC for the determination amphetamines and related derivatives. Studies have shown the determination of amphetamine and related derivatives in plasma, urine, and hair by RP-HPLC with precolumn derivatization and either UV/VlS or fluorescence detection. Various methods are employed by SPE technologies using Cl8 cartridges for sample cleanup prior to derivatization. The derivatized compounds were separated on analytical columns of various Cl 8 bonded phase materials. The methods generally used water/acetonitrile mobile phases operated in gradient mode. All studies reported extraction recoveries of 85-102% for all the analytes, with LLOQs ranging from 5 to 60 ng/ml (Tedeschi et al., 1993 Ealco et al., 1996 Hernandez et al., 1997 Al-Dirbashi et al., 1997 Al-Dirbashi et al., 2000 Soares et al., 2001). 

Falco P, Cabeza A, Legua C, Kohhnann M. 1996. Amphetamine and methamphetamine determination in urine by reversed-phase high-performance liquid chromatography with simultaneous sample clean-up and derivatization with naphthoquinone 4-sulphonate on solid-phase cartridges. J Chromatogr B Biomed Sci Appl 687(1) 239-246. 

Hernandez R, Falco P, Cabeza A. 1997. Liquid chromatographic analysis of amphetamine and related compounds in urine using solid-phase extraction and 3,5-dinitrobenzoyl chloride for derivatization. J Chromatogr Sci 35(4) 169-175. 

Soares ME, Carvalho F, Bastos ML. 2001. Determination of amphetamine and its metabolite p-hydroxyamphetamine in rat urine by reversed-phase high-performance liquid chromatography after dabsyl derivatization. Biomed Chromatogr 15(7) 452-426. 

We have derivatized and observed other drugs such as morphine, codeine, amphetamine, and meperidine with similar results. Cocaine could not be derivatized under the conditions that we employed and was only detected as the protonated molecular ion. 

Koster et al. [140] conducted on-fiber derivatization for SPME to increase the detectability and extractability of drugs in biological samples. Amphetamine was used as a model compound. The extraction was performed by direct immersion of a 100-pm polydimethylsiloxane-coated fiber into buffered human urine. On-fiber derivatization was performed with pentafluorobenzoyl chloride either after or simultaneously with extraction. 

One of the most commonly used class of derivatization agents for diasteromer formation are isothiocyanates and isocyanates. Enantiomers of /3-blockers, amphetamine, epinephrine, methamphetamine, and mexiletine have been resolved after derivatization with these agents. Isothiocyanates produce thiourea derivatives upon reaction with primary and secondary amines. Thiourea derivatives also provide a strong UV absorbance for the detection of enantiomers lacking a strong UV chromophore. Isocyanates produce ureas when reacted with amines. The physical properties of these ureas are similar to thiourea derivatives. Isocyanates will also react with alcohols to yield carbamates. 

Veuthey and Haerdi reported the separation of amphetamines using packed-column SFC [26]. The amphetamines were derivatized with 9-fluorenylmethyl chloroformate and chromatographed with a methanol or 2-propanol-modified carbon dioxide as the mobil phase. The separations were compared on bare silica and aminopropyl-bonded silica columns. Both columns gave comparable results and the separation of all five amphetamines (methylamphetamine, amphetamine, phenethylamine, ephed-rine, and norephedrine) was achieved in less than 5 min. Both methanol and 2-propanol-modified carbon dioxide gave comparable results. It was observed that the modifier concentration had more effect on the solvating power than the mobile-phase density. 

F. X. Zhou and I. S. Krull, Direct enantiomeric analysis of amphetamine in plasma by simultaneous solid phase extraction and chiral derivatization, Chromatographia, 55 153 (1993). 

Nishida M, Yashiki M, Namera A, Kimura K (2006) Single hair analysis of methamphetamine and amphetamine by solid phase microextraction coupled with in matrix derivatization. J ChromatogrB Analyt TechnolBiomedLifeSci 842(2) 106-110. doi S 1570-0232(06)00580-0 [pii] 10.1016/j. j chromb.2006.07.039... 

Ramseier A, von Heeren F, Thormann W. Analysis of fluorescein isothiocyanate derivatized amphetamine and analogs in human urine by capillary electrophoresis in chip-based and fused-silica capillary instrumentation. Electrophoresis 1998 19 2967-2975. 

Takahashi reported the detectioir of methamphetamine and amphetamine in hairs of monkeys after administration of methamphetamine. He used trifluoroacetic anhydride (TFAA) for derivatization and OV-101 as the GC column. He found the highest amount of both compounds in the fourth week. Then they decreased gradually. Nagai et al. presented a method for the detection of methamphetamine and amphetamine in hair of addicts, as well as in hair, bones, and teeth after animal experiments. They used a packed column (PC) with 5% PEG 6000 + 5%-KOH and M-ethylbenzylamine as the internal standard (IS). 

The GC/MS procedures for methamphetamine are described in Table 4. The papers published in Japanese - have corresponding reports in English. - - Methamphetamine was detected and determined by mass fragmentography in rat hair after administration of the substance. Nine methods also detected the metabolite amphetamine or amphetamine alone. Suzuki et al. determined methamphetamine also in nail, sweat and saliva. The workup (EX after acid or alkaline hydrolysis) and derivatization technique (methanol-trifluoroacetic acid [TEA]) is rather uniform in most procedures. Nakahara et al. ° used methoxyphenamine excretion into beard hair to discuss several washing procedures. Alkaline or methanolic extraction are used with one exception. Derivatization is mainly made by fluorinated anhydrides. A review ° gives details on analytical procedures, incorporation rates of amphetamines from blood to hair, and relationship between drug history and drug distribution in hair. 

Summary of Pretreatment of Hair Samples, Extraction, Derivatization, and Ranges of Concentration for Amphetamines in Hair... 

In order to alleviate this problem, derivatization can be employed. One of the easiest processes, for the analysis of amphetamine, is to derivatize directly with carbon disulfide and it is this method which finds wide application in the United Kingdom. For bulk and trace samples, this is achieved by dissolving the material... 

The reaction (see equation (2.1)) is a simple, pre-column derivatization, involving the amino group of the amphetamine and the CS2. This process reduces the polarity of the product, improving its chromatographic behaviour and hence the sensitivity of the method. In addition, it results... 

One difficulty with this method is that the derivatization process will not work for secondary amines such as methylamphetamine and 3,4-methylenedioxy methylamphetamine (MDMA). An alternative method for derivatization is therefore required in such cases. One such technique is the derivatization of the amphetamine samples with heptafluorobutyric anhydride (HFBA) [8]. 

In this system, amphetamine, 3,4-methylenedioxyamphetamine (MDA) and the A-methyl and A-ethyl analogues of the drugs were derivatized, with 4-chloroamphetamine being used as the internal standard. For powders, solutions were prepared at concentrations of 1 mgml in methanol and a 100 til aliquot blown dry under nitrogen. To the residue was added 50 p.1 of 0.5 M KOH and 500 p,l of toluene. The mixture was then shaken for 30 s and centrifuged, after which the toluene layer was recovered and HFBA (5 til) added. The excess reagent was neutralized with 500 p,l of 10% NaHCOs and an aliquot (1 ttl) analysed by GC-MS. Each of the amphetamines and the A-alkylated derivatives could be separated and identified on the basis of retention index and mass spectral data. 

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