Stability Study of Propoxur (Baygon) in Whole Blood and Urine Stored at Varying Temperature Conditions

• Published in: Journal of analytical toxicology Vol. 30; no. 5; pp. 313 - 316
• Main Authors: Ramagiri, Suma, Kosanam, Hari, Prakash, P.K. Sai
• Format: Journal Article
• Language: English
• Published: Niles, IL Oxford University Press 01.06.2006; Preston
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, High Pressure Liquid; Exact sciences and technology; Humans; Insecticides - blood; Insecticides - chemistry; Insecticides - urine; Other chromatographic methods; Propoxur - blood; Propoxur - chemistry; Propoxur - urine; Specimen Handling - methods; Spectrometry, Mass, Electrospray Ionization; Temperature; Urine; Validation; Solid phase extraction; Biological fluid; Chemical analysis; Insecticide; Coupled method; Pesticides; HPLC chromatography; Temperature effect; Organic carbamate; Electrospray; Operating conditions; Chemical enrichment; Whole blood; Ultraviolet detector; Sample preparation; Storage stability; Mass spectrometry; Quantitative analysis
• ISSN: 0146-4760; 1945-2403
• DOI: 10.1093/jat/30.5.313

A stability study has been initiated for propoxur (Baygon) in whole blood and urine samples stored over a period of 60 days at four different temperature conditions (room temperature, 4°C, −20°C, and −80°C). Stability data was established on day 0, 1, 7, 14, 28, 42, and 60. Sample purification was done by solid-phase extraction using a weak cation exchange cartridge (Isolute® CBA), and quantitation was carried out by a validated high-performance liquid chromatographic method with a photodiode-array UV detector. Propoxur was spiked at two different concentration levels in both blood and urine samples [low concentration (10 µg/L) and high concentration (100 µg/L)]. Isopropoxy phenol was observed as the major degradation product in blood and urine samples and confirmed by liquid chromatography-electrospray ionization-mass spectrometry. At room temperature, a substantial decrease in concentration of about 95% was observed at the end of the stability study in both blood and urine samples. However, at 4°C, the concentration of propoxur observed after 60 days was around 60% in both samples. A decrease in temperature reduced the degradation, and finally propoxur was found to be stable at −80°C and −20°C for the whole observation period (60 days). The data collected suggests that knowledge about time-dependent decrease of propoxur in urine and blood samples is of considerable significance in forensic toxicology, and, therefore, forensic cases should be interpreted with caution.