MilliporeSigma
  • Quantitative analysis of zopiclone, N-desmethylzopiclone, zopiclone N-oxide and 2-amino-5-chloropyridine in urine using LC-MS-MS.

Quantitative analysis of zopiclone, N-desmethylzopiclone, zopiclone N-oxide and 2-amino-5-chloropyridine in urine using LC-MS-MS.

Journal of analytical toxicology (2014-05-03)
Gunnel H Nilsson, Fredrik C Kugelberg, Johan Ahlner, Robert Kronstrand
ABSTRACT

A simple liquid chromatography-tandem mass spectrometry method was validated to allow determination of zopiclone (ZOP), N-desmethylzopiclone (NDZOP), zopiclone N-oxide (ZOPNO) and 2-amino-5-chloropyridine (ACP) in urine at concentrations up to 3,000 ng/mL within 3.5 min. This method was used for quantitative analysis of the analytes in authentic urine samples obtained 10 h after oral administration of zopiclone (Imovane(®)) and in aliquots of the same urine samples after different storage conditions. In addition, pH of each studied urine sample was measured over time. The results showed that formation of ACP occurred at elevated pH and/or temperature by degradation of ZOP, NDZOP and ZOPNO. This method was also applied to samples obtained from two female victims of drug-facilitated assault. One sample had been exposed to long-term storage conditions at different temperatures and at pH >8.2, which resulted in high concentrations of ACP. The other sample, which was exposed to pH <6.5, showed no formation of ACP. ACP is formed both from ZOP and from its metabolites NDZOP and ZOPNO depending on the pH of the urine, time of storage and/or the temperature conditions. For correct interpretation in forensic cases, ZOP, its major metabolites and ACP should be analyzed. When ACP is identified in urine, the concentrations of ZOP, NDZOP and ZOPNO should be interpreted with great caution.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Ammonium acetate, reagent grade, ≥98%
Sigma-Aldrich
Sodium acetate trihydrate, BioXtra, ≥99.0%
Supelco
Ammonium acetate, LiChropur, eluent additive for LC-MS
Sigma-Aldrich
Ammonium acetate, BioUltra, for molecular biology, ≥99.0%
Sigma-Aldrich
Sodium acetate trihydrate, BioUltra, ≥99.5% (NT)
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (v/v) trifluoroacetic acid
Sigma-Aldrich
Acetic acid-12C2, 99.9 atom % 12C
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Sigma-Aldrich
Acetic acid, ≥99.5%, FCC, FG
Sigma-Aldrich
Ammonium acetate, BioXtra, ≥98%
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) formic acid, suitable for HPLC
Sigma-Aldrich
Ammonium acetate, 99.999% trace metals basis
Sigma-Aldrich
Acetonitrile solution, contains 10.0% acetone, 0.05% formic acid, 40.0% 2-propanol
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (w/v) ammonium formate, 5 % (v/v) water, 0.1 % (v/v) formic acid, suitable for HPLC
Sigma-Aldrich
Methanol solution, NMR reference standard, 4% in methanol-d4 (99.8 atom % D), NMR tube size 3 mm × 8 in.
Sigma-Aldrich
Acetic acid, natural, ≥99.5%, FG
Sigma-Aldrich
Sodium acetate trihydrate, meets USP testing specifications
Sigma-Aldrich
Ammonium acetate, for molecular biology, ≥98%
Supelco
Methanol solution, contains 0.10 % (v/v) formic acid, UHPLC, suitable for mass spectrometry (MS), ≥99.5%
Supelco
Residual Solvent - Acetonitrile, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Sodium acetate trihydrate, puriss., meets analytical specification of Ph. Eur., BP, USP, FCC, E262, 99.0-101.0% (calc. to the dried substance), ≤0.00002% Al
Sigma-Aldrich
Ammonium acetate, ACS reagent, ≥97%
Sigma-Aldrich
Sodium acetate trihydrate, ACS reagent, ≥99%
Sigma-Aldrich
Sodium acetate trihydrate, ReagentPlus®, ≥99.0%
Sigma-Aldrich
Ammonium acetate, ≥99.99% trace metals basis
Sigma-Aldrich
Ammonium acetate solution, for molecular biology, 7.5 M
Sigma-Aldrich
5α-Androstan-17β-ol-3-one, ≥97.5%
Sigma-Aldrich
Acetic acid, for luminescence, BioUltra, ≥99.5% (GC)
Supelco
Acetonitrile, analytical standard
Sigma-Aldrich
Acetonitrile, ≥99.5%, ACS reagent