1. The use of cyclohexanone as a “derivatizing” reagent for the GC–MS detection of amphetamines and ephedrines in seizures and the urine 
B.M. El-Haj, A.M. Al-Amri, M.H. Hassan, H.S. Ali, R.K. Bin Khadem 
Forensic Science International 
Volume 135, Issue 1, Pages (July 2003)
DOI: /S (03)

2. Fig. 1
The mass spectra of the acetyl derivative of methamphetamine (A) and the diacetyl derivative of pseudoephedrine (B), as obtained from PMW_TOX2 mass-spectra library. The significant similarity of the two mass spectra together with the very low abundance of the molecular ion (M) in (A) at m/z=191 and the absence of M in (B) should be noted.
Forensic Science International  , 16-26DOI: ( /S (03) )

3. Fig. 2
Reactions of primary amines (A) and secondary amines (B) with carbonyl compounds.
Forensic Science International  , 16-26DOI: ( /S (03) )

4. Fig. 3
Reactions of the ephedrines and the amphetamines with cyclohexanone at high temperatures.
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5. Fig. 4
EI mass spectra of the cyclohexanone derivatives of amphetamine (A), methamphetamine (B), ephedrine (C), pseudoephedrine (D) and phenylpropanolamine (norephedrine) (E). Molecular ion (M).
Forensic Science International  , 16-26DOI: ( /S (03) )

6. Fig. 4
EI mass spectra of the cyclohexanone derivatives of amphetamine (A), methamphetamine (B), ephedrine (C), pseudoephedrine (D) and phenylpropanolamine (norephedrine) (E). Molecular ion (M).
Forensic Science International  , 16-26DOI: ( /S (03) )

7. Fig. 5
Amphetamine as an impurity in a methamphetamine seizure. Extracted-ion chromatogram obtained from the GC–MS analysis of a methamphetamine seizure, upon using cyclohexanone as “derivatizing” reagent. The ratio m/z of 124 (base peak ion for amphetamine-CXCP) and 138 (base peak ion for methamphetamine-CXCP) were used in the extraction of the ion-chromatogram. The retention times and EI mass spectral ions for the two compounds (a) amphetamine-CXCP and (b) methamphetamine-CXCP are the same as those for the corresponding reference substances in Fig. 4(A) and (B). Cyclohexanone condensation product (CXCP).
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8. Fig. 6
Amphetamine as a metabolite of methamphetamine. Extracted-ion chromatogram obtained from the GC–MS analysis of the urine of a methamphetamine user, upon using cyclohexanone as “derivatizing” reagent. The ratio m/z of 124 (base peak ion for amphetamine-CXCP) and 138 (base peak ion for methamphetamine-CXCP) were used in the extraction of the ion-chromatogram. The retention times and EI mass spectral ions for the two compounds (a) amphetamine-CXCP and (b) methamphetamine-CXCP, are the same as those for the corresponding reference substances in Fig. 4(A) and (B). Cyclohexanone condensation product (CXCP).
Forensic Science International  , 16-26DOI: ( /S (03) )

9. Fig. 7
Norpseudoephedrine as metabolite of pseudoephedrine extracted-ion chromatogram obtained from the GC–MS analysis of the urine of a pseudoephedrine user, upon using cyclohexanone as “derivatizing” reagent. The ratio m/z of 125 (base peak ion of norpseudoephedrine-CXCP) and 202 (base peak ion of pseudoephedrine-CXCP) were used in the extraction of the ion chromatogram. The retention times and EI mass spectral ions for the two compounds (a) norpseudoephedrine-CXCP (norpseudoephedrine is also known as phenylpropanolamine) and (b) pseudoephedrine-CXCP, are the same as those for the corresponding reference substances in Fig. 4(E) and (D). Cyclohexanone condensation product (CXCP).
Forensic Science International  , 16-26DOI: ( /S (03) )

10. Fig. 8
Demonstration of Khat use. Extracted-ion chromatogram and EI mass spectrum ions (table) obtained from the GC–MS analysis of the urine of a Khat user, upon using cyclohexanone as “derivatizing” reagent. The ratio m/z of 125 (base peak ion for the two cyclohexanone derivatives), was used in the extraction of the ion-chromatograms.
Forensic Science International  , 16-26DOI: ( /S (03) )