The effect of sodium fluoride preservative and storage temperature on the stability of cocaine in horse blood, sheep vitreous and deer muscle
Authors: Rees, K.A., Jones, N.S., McLaughlin, P.A., Seulin, S., Leyton, V., Yonamine, M. and Osselton, M.D.
Journal: Forensic Science International
Volume: 217
Issue: 1-3
Pages: 182-188
eISSN: 1872-6283
ISSN: 0379-0738
DOI: 10.1016/j.forsciint.2011.11.001
Abstract:The in vitro stability of cocaine in horse blood, sheep vitreous humour (VH) and homogenised deer muscle is described. The stability of cocaine in horse blood was of interest because many toxicology laboratories utilise horse blood for the preparation of calibration and check standards and the latter are typically stored during routine use. The storage stability of cocaine in human VH and muscle has not been previously reported. In the absence of blank human VH and muscle, cocaine stability under varying conditions was demonstrated in animal tissues. Blood and VH were stored with and without addition of NaF at room temperature (RT), 4 °C and -18 °C for 84 days. Muscle homogenates were prepared in water, water/2% NaF, and phosphate buffer (pH 6.0)/2% NaF, and stored for 31 days at RT, 4 °C and -18 °C. Cocaine stability in human muscle obtained from cocaine positive forensic cases was assessed following storage at -18 °C for 13 months. Cocaine and benzoylecgonine (BZE) were extracted using SPE and quantified by GC-MS/MS. Cocaine was stable for 7 days in refrigerated (4 °C) horse blood fortified with 1 and 2% NaF. In the absence of NaF, cocaine was not detectable by day 7 in blood stored at RT and 4 °C and had declined by 81% following storage at -18 °C. At 4 °C the rate of cocaine degradation in blood preserved with 2% NaF was significantly slower than with 1% NaF. The stability of cocaine in horse blood appeared to be less than that reported for human blood, probably attributable to the presence of carboxylesterase in horse plasma. Cocaine stored in VH at -18 °C was essentially stable for the study period whereas at 4 °C concentrations decreased by >50% in preserved and unpreserved VH stored for longer than 14 days. Fluoride did not significantly affect cocaine stability in VH. The stability of cocaine in muscle tissue homogenates significantly exceeded that in blood and VH at every temperature. In preserved and unpreserved samples stored at 4 °C and below, cocaine loss did not exceed 2%. The increased stability of cocaine in muscle was attributed to the low initial pH of post-mortem muscle. In tissue from one human case stored for 13 months at -18 °C the muscle cocaine concentration declined by only 15% (range: 5-22%). These findings promote the use of human muscle as a toxicological specimen in which cocaine may be detected for longer compared with blood or VH. © 2011 Elsevier Ireland Ltd.
Source: Scopus
The effect of sodium fluoride preservative and storage temperature on the stability of cocaine in horse blood, sheep vitreous and deer muscle.
Authors: Rees, K.A., Jones, N.S., McLaughlin, P.A., Seulin, S., Leyton, V., Yonamine, M. and Osselton, M.D.
Journal: Forensic Sci Int
Volume: 217
Issue: 1-3
Pages: 182-188
eISSN: 1872-6283
DOI: 10.1016/j.forsciint.2011.11.001
Abstract:The in vitro stability of cocaine in horse blood, sheep vitreous humour (VH) and homogenised deer muscle is described. The stability of cocaine in horse blood was of interest because many toxicology laboratories utilise horse blood for the preparation of calibration and check standards and the latter are typically stored during routine use. The storage stability of cocaine in human VH and muscle has not been previously reported. In the absence of blank human VH and muscle, cocaine stability under varying conditions was demonstrated in animal tissues. Blood and VH were stored with and without addition of NaF at room temperature (RT), 4°C and -18°C for 84 days. Muscle homogenates were prepared in water, water/2% NaF, and phosphate buffer (pH 6.0)/2% NaF, and stored for 31 days at RT, 4°C and -18°C. Cocaine stability in human muscle obtained from cocaine positive forensic cases was assessed following storage at -18°C for 13 months. Cocaine and benzoylecgonine (BZE) were extracted using SPE and quantified by GC-MS/MS. Cocaine was stable for 7 days in refrigerated (4°C) horse blood fortified with 1 and 2% NaF. In the absence of NaF, cocaine was not detectable by day 7 in blood stored at RT and 4°C and had declined by 81% following storage at -18°C. At 4°C the rate of cocaine degradation in blood preserved with 2% NaF was significantly slower than with 1% NaF. The stability of cocaine in horse blood appeared to be less than that reported for human blood, probably attributable to the presence of carboxylesterase in horse plasma. Cocaine stored in VH at -18°C was essentially stable for the study period whereas at 4°C concentrations decreased by >50% in preserved and unpreserved VH stored for longer than 14 days. Fluoride did not significantly affect cocaine stability in VH. The stability of cocaine in muscle tissue homogenates significantly exceeded that in blood and VH at every temperature. In preserved and unpreserved samples stored at 4°C and below, cocaine loss did not exceed 2%. The increased stability of cocaine in muscle was attributed to the low initial pH of post-mortem muscle. In tissue from one human case stored for 13 months at -18°C the muscle cocaine concentration declined by only 15% (range: 5-22%). These findings promote the use of human muscle as a toxicological specimen in which cocaine may be detected for longer compared with blood or VH.
Source: PubMed
The effect of sodium fluoride preservative and storage temperature on the stability of 6-acetylmorphine in horse blood, sheep vitreous and deer muscle
Authors: Rees, K.A., Jones, N.S., McLaughlin, P.A. and Osselton, M.D.
Journal: FORENSIC SCIENCE INTERNATIONAL
Volume: 217
Issue: 1-3
Pages: 189-195
ISSN: 0379-0738
DOI: 10.1016/j.forsciint.2011.11.002
Source: Web of Science (Lite)
The effect of sodium fluoride preservative and storage temperature on the stability of cocaine in horse blood, sheep vitreous and deer muscle.
Authors: Rees, K.A., Jones, N.S., McLaughlin, P.A., Seulin, S., Leyton, V., Yonamine, M. and Osselton, M.D.
Journal: Forensic science international
Volume: 217
Issue: 1-3
Pages: 182-188
eISSN: 1872-6283
ISSN: 0379-0738
DOI: 10.1016/j.forsciint.2011.11.001
Abstract:The in vitro stability of cocaine in horse blood, sheep vitreous humour (VH) and homogenised deer muscle is described. The stability of cocaine in horse blood was of interest because many toxicology laboratories utilise horse blood for the preparation of calibration and check standards and the latter are typically stored during routine use. The storage stability of cocaine in human VH and muscle has not been previously reported. In the absence of blank human VH and muscle, cocaine stability under varying conditions was demonstrated in animal tissues. Blood and VH were stored with and without addition of NaF at room temperature (RT), 4°C and -18°C for 84 days. Muscle homogenates were prepared in water, water/2% NaF, and phosphate buffer (pH 6.0)/2% NaF, and stored for 31 days at RT, 4°C and -18°C. Cocaine stability in human muscle obtained from cocaine positive forensic cases was assessed following storage at -18°C for 13 months. Cocaine and benzoylecgonine (BZE) were extracted using SPE and quantified by GC-MS/MS. Cocaine was stable for 7 days in refrigerated (4°C) horse blood fortified with 1 and 2% NaF. In the absence of NaF, cocaine was not detectable by day 7 in blood stored at RT and 4°C and had declined by 81% following storage at -18°C. At 4°C the rate of cocaine degradation in blood preserved with 2% NaF was significantly slower than with 1% NaF. The stability of cocaine in horse blood appeared to be less than that reported for human blood, probably attributable to the presence of carboxylesterase in horse plasma. Cocaine stored in VH at -18°C was essentially stable for the study period whereas at 4°C concentrations decreased by >50% in preserved and unpreserved VH stored for longer than 14 days. Fluoride did not significantly affect cocaine stability in VH. The stability of cocaine in muscle tissue homogenates significantly exceeded that in blood and VH at every temperature. In preserved and unpreserved samples stored at 4°C and below, cocaine loss did not exceed 2%. The increased stability of cocaine in muscle was attributed to the low initial pH of post-mortem muscle. In tissue from one human case stored for 13 months at -18°C the muscle cocaine concentration declined by only 15% (range: 5-22%). These findings promote the use of human muscle as a toxicological specimen in which cocaine may be detected for longer compared with blood or VH.
Source: Europe PubMed Central