Erschienen in:
09.05.2018 | Original Article
Long-term stability of synthetic cathinones in dried blood spots and whole blood samples: a comparative study
verfasst von:
Kelly Francisco da Cunha, Marcos Nogueira Eberlin, Jose Luiz Costa
Erschienen in:
Forensic Toxicology
|
Ausgabe 2/2018
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Abstract
Purpose
The long-term stability of four synthetic cathinones in dried blood spots (DBS) were tested and compared with those of whole blood samples.
Method
A method to determine four cathinones (pentylone, butylone, mephedrone and benzedrone) in DBS was developed and validated. For comparison, the traditional liquid-liquid extraction for the same analytes in whole blood was also performed.
Results
The calibration curve was found to be linear over 25–1000 ng/mL for DBS samples, with a limit of quantification (LOQ) at 25 ng/mL. The interday imprecision and bias results [up to 7.1% relative standard deviation (RSD) and 5.8%, respectively] were much lower than the maximum data recommended by SWGTOX guidelines. The validation results were similar to those of whole blood samples, which showed interday imprecision and bias results of up to 8.1%RSD and 12.3%, respectively, with a linear calibration curve between 10 and 1000 ng/mL and LOQ of 10 ng/mL. A stability study to compare the degradation rate between both matrices at three storage temperatures [room temperature (25 °C), 4 and − 20 °C] and during 90 days proved the poor stability of cathinones in whole blood, where the methylenedioxy cathinones displayed better stability than those with ring substituents. DBS allowed detection of synthetic cathinones after much longer periods than in whole blood samples.
Conclusions
DBS proved, therefore, to be an useful alternative technique to store blood samples. Extraction of DBS is easy and analytes remain stable for much longer periods.