Simultaneous determination of morphine, codeine and 6-acetyl morphine in human urine and blood samples using direct aqueous derivatisation: Validation and application to real cases

• We developed new methods for aqueous derivatisation of morphine, codeine and 6-MAM.
• The methods can be applied to human urine and blood samples.
• The procedures are easy to perform in laboratories with limited resources.
• They can be used in daily laboratory activity.

Opiates play a relevant role in forensic toxicology and their assay in urine or blood is usually performed for example in workplace drug-testing or toxicological investigation of drug impaired driving. The present work describes two new methods for detecting morphine, codeine and 6-monoacethyl morphine in human urine or blood using a single step derivatisation in aqueous phase. Propyl chloroformate is used as the dramatizing agent followed by liquid–liquid extraction and gas-chromatography–mass spectroscopy to detect the derivatives. The methods have been validated both for hydrolysed and unhydrolysed urine.For hydrolysed urine, the LOD and LOQ were 2.5 ng/ml and 8.5 ng/ml for codeine, and 5.2 ng/ml and 15.1 ng/ml for morphine, respectively. For unhydrolysed urine, the LOD and LOQ were 3.0 ng/ml and 10.1 ng/ml for codeine, 2.7 ng/ml and 8.1 ng/ml for morphine, 0.8 ng/ml and 1.5 ng/ml for 6-monoacetyl morphine, respectively. In blood, the LOD and LOQ were 0.44 ng/ml and 1.46 ng/ml for codeine, 0.29 ng/ml and 0.98 ng/ml for morphine, 0.15 ng/ml and 0.51 ng/ml for 6-monoacetyl morphine, respectively.The validated methods have been applied to 50 urine samples and 40 blood samples (both positive and negative) and they can be used in routine analyses.