Trace determination of morphine and codeine in whole blood samples using pH‐switchable hydrophobic deep eutectic solvents based liquid phase microextraction followed by HPLC‐UV

An environmental friendly, fast, easy and inexpensive pH‐switchable hydrophobic deep eutectic solvent‐based liquid phase microextraction procedure was developed and combined with HPLC−UV detection for the extraction and analysis of morphine and codeine in whole blood samples. In this method, seven deep eutectic solvents were synthesized and then their switchability with pH was investigated. Deep eutectic solvents that could be switched with pH were used as extractant. Under the optimum conditions, relative standard deviation values for intra‐day and inter‐day of the method based on seven replicate measurements of 50 μg L –1 of morphine and codeine in blood samples were in the range of 3.7–4.3% and 5.4–6.2%, respectively. The calibration graphs were linear in the range of 1.5–300 μg L –1 and limit of detection for both analytes was 0.5 μg L –1 . The enrichment factor and the extraction recovery of morphine and codeine were in the ranges of 152−166, and 76−83%, respectively. The results showed that both morphine and codeine were detected in the blood sample of the addicted person. The relative recoveries of real blood samples which have been spiked with different levels of morphine and codeine were 91.8–107.0%. This article is protected by copyright. All rights reserved