The effect of sodium fluoride preservative and storage temperature on the stability of 6-acetylmorphine in horse blood, sheep vitreous and deer muscle

This study examined the in vitro stability of 6-acetylmorphine (6AM) in horse blood, sheep vitreous humour (VH) and homogenised deer muscle stored under different storage conditions. The stability of 6AM in horse blood is of interest because many toxicological laboratories utilise this matrix for the preparation of blood calibration and check standards and the latter are typically stored during routine use. Data on the storage stability of 6AM in human VH is extremely limited and no data has been reported in muscle. In the absence of human samples, 6AM stability was demonstrated in sheep vitreous and deer muscle. Blood and VH were stored with and without NaF at room temperature (RT), 4 and -18°C for 84 days. Muscle tissue homogenates were prepared in water with and without NaF and also in phosphate buffer (pH 6.0) containing NaF. Homogenates were stored for 31 days at RT, 4 and -18°C. Morphine and 6AM were extracted using SPE and quantified by GC-ion trap-MS/MS. In the absence of NaF, 6AM could not be detected after 7 and 14 days in blood stored at RT and 4°C, respectively. Although at -18°C 6AM was stable for 7 days (12% loss), only 54% was detected by day 84. The addition of NaF to horse blood increased 6AM stability substantially at every temperature. Further, the rate of degradation was found to be significantly slower in blood preserved with 2% NaF compared with 1% NaF (p=.05). 6AM was stable for the study period in preserved blood (1 and 2% NaF) stored at -18°C. For laboratories utilising horse blood in the preparation of standards, preservation with 1% NaF (minimum) and storage at -18°C is recommended. The addition of NaF to VH was essential for 6AM stability. Irrespective of temperature substantial losses (≥ 42%) were observed in unpreserved sheep VH by day 7. In preserved VH the concentration declined by only 22% on day 7 following storage at RT and no loss observed in VH stored at 4 and -18°C at the same time. In muscle, 6AM was stable for 7 days in preserved samples stored at RT and in all samples stored at 4°C and below. The addition of NaF increased the stability of 6AM substantially in muscle. The increased stability of 6AM in VH and muscle preserved with fluoride was attributed to inhibition of bacterial action and the subsequent reduction in the rate of putrefaction of these tissues.     

Detection of cocaine in blood stains]

Cocaine is rapidly degraded in blood samples, and its degradation was found to be highly dynamic in nature. The analysis of blood spots dried on filter paper may provide a method to minimize the break-down of cocaine and to largely preserve the analytical profile of the parent drug and its hydrolysis products at the time of sampling. The short term stability of cocaine in 100 microL blood spots prepared from unpreserved and preserved (sodium fluoride, 0.25%) blood samples was compared to the stability of the particular whole blood specimens stored in tubes at ambient temperature and at -20 degrees C. Due to dehydration, both the chemical and the enzymatic hydrolysis of cocaine and its products could be stopped in dried blood spots. More than 75% of the initial cocaine concentration could be detected in the blood spots, and the analytical profile was ensured for 17 days. Provided its practical suitability, the spot technology should offer a simple approach to detect actual impairment of motorists taken in police custody in the view of section 24a of the German traffic act as well as in cocaine associated criminal cases.     

Relationships between concentrations of cocaine and its hydrolysates in peripheral blood, heart blood, vitreous humor and urine

Cocaine is known to degrade in vivo and in vitro by several hydrolytic mechanisms. A previous study found that the initial amount of cocaine added to plasma could be accounted for by summing the molar concentrations of cocaine's hydrolysis products and the cocaine remaining after hydrolysis. The present study was undertaken to investigate whether or not relationships might exist between such molar concentration sums for different postmortem bodily fluids. Determinations of cocaine, benzoylecgonine, ecgonine methyl ester, and ecgonine were performed using liquid chromatography/mass spectrometry (LC/MS/MS) with heart blood, femoral blood, vitreous humor (VH), and urine (UR). The results demonstrate a strong correlation between blood and VH concentrations (correlation coefficients of 0.88-0.94), weak correlation between the UR and blood concentrations (correlation coefficients of 0.61-0.64), and weak correlation between UR and VH concentrations (correlation coefficient of 0.59). The results demonstrate that ecgonine is a significant hydrolysate with concentrations on the same order of magnitude as benzoylecgonine. The results are consistent with rapid distribution of the parent drug and its hydrolysates in the blood and VH. The strong correlation between the blood and VH demonstrates that VH is an important medium for toxicology testing when attempting to make a determination of cocaine intoxication.     

Studies on the stability and detection of cocaine, benzoylecgonine, and 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid in whole blood using Abuscreen radioimmunoassay

A study was undertaken to assess the stability and the radioimmunoassay (RIA) detection of cocaine, benzoylecgonine (BZE), and 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in whole blood while stored in 4 different kinds of blood collection tubes for up to 30 days at refrigeration and room temperatures. At various intervals, the tubes were sampled and analyzed using Abuscreen RIA. Also, semi-quantitative data derived from RIA analysis of forensic blood specimens were compared with quantitative data acquired using gas chromatography (GC) or GC/mass spectrometry (GC/MS) on the same specimens. RIA and chromatographic studies revealed that BZE and THC-COOH were stable in blood under all conditions studied. Cocaine, however, was found not to be stable in blood, especially when stored at room temperatures. Despite cocaine's instability in blood, RIA was able to detect the presence of cocaine and its breakdown products in blood under all conditions studied.     

Brain concentrations of cocaine and benzoylecgonine in fatal cases

Since cocaine in blood rapidly hydrolyzes to benzoylecgonine, cocaine concentrations determined in postmortem blood may not reflect the presence or concentration of cocaine in the body at the time of death. The interpretative value of the determination of cocaine and benzoylecgonine in brain tissue was investigated. Cocaine and benzoylecgonine were quantitated by coextraction and formation of the propyl derivative of benzoylecgonine followed by selected ion monitoring gas chromatography/mass spectrometry (GC/MS) using electron ion impact ionization. Cocaine and benzoylecgonine were found to be evenly distributed throughout the brain. Cocaine and benzoylecgonine concentrations were stable in frozen brain tissue (-4 degrees C) on reanalysis after 1 to 3 months of storage, and in refrigerated tissue (10 degrees C) after 30 days of storage. Blood, brain, and liver concentrations of cocaine and benzoylecgonine in 37 cocaine overdose cases and 46 cases in which cocaine was incidental to the cause of death were reviewed. The ratios of cocaine/benzoylecgonine in the toxic cases (brain mean 14.7 and blood mean 0.64) were clearly different from those found in the incidental cases (brain mean 0.87 and blood mean 0.27). The brain/blood ratios of cocaine and benzoylecgonine concentrations generally were characteristic of the time elapsed since cocaine dosing. In cocaine overdose cases, the mean ratio was 9.6 for cocaine and 0.36 for benzoylecgonine. These are within the range found in animal studies for brain/blood ratios of cocaine and benzoylecgonine 0.5 to 2 h after cocaine administration. In incidental cases, the brain/blood ratios were mean 2.5 for cocaine and 1.4 for benzoylecgonine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Gamma-hydroxybutyric acid stability and formation in blood and urine

Gamma-hydroxybutyric acid (GHB) can cause problems in interpretation of toxicological findings due to its endogenous nature, significant production in tissues after death and potential formation in stored samples. Our study was designed to determine the influence of storage conditions on GHB levels and its possible in vitro formation in blood and urine in cases where no exogenous use of GHB or its precursors was suspected. The samples were prepared by validated method based on liquid-liquid reextraction with adipic acid internal standard and MSTFA derivatization and assayed on a GC-MS operating in EI SIM mode. The first part of the study was performed with pooled blood and urine samples obtained from living and deceased subjects stored with and without NaF (1% w/v) at 4 and -20 degrees C over 8 months. In ante-mortem samples (both blood and urine) no significant GHB production was found. After 4 months of storage, the substantial GHB rise up to 100 mg/Lwas observed in post-mortem blood stored at 4 degrees C without NaF with subsequent gradual decrease in following months. The inhibition of GHB production was apparent during storage in NaF treated frozen blood samples. In post-mortem urine only slight temporary GHB levels were ascertained (up to 8 mg/L). The second part of our study was aimed to analyse 20 individual post-mortem blood samples stored at 4 degrees C for 16-27 days between autopsy and analysis without preservation followed by storage at 4 degrees C with NaF for 4 months. The temporary GHB production with maximum of 28 mg/Lwas detected in some samples.     

Stability of Morphine,Codeine, and 6‐Acetylmorphine in Blood at Different Sampling and Storage Conditions

The stability of drugs in biological specimens is a major concern during the evaluation of the toxicological results. The stability of morphine, codeine, and 6‐acetyl‐morphine in blood was studied after different sampling conditions: (i) in glass, polypropylene or polystyrene tubes, (ii) with addition of dipotassium ethylene diamine tetraacetic acid (K₂EDTA) or sodium oxalate (Na₂C₂O₄), and (iii) with or without the addition of sodium fluoride (NaF). Spiked blood samples were stored at two different temperatures (4 and ?20^°C), analyzed after different storage times and after three freeze–thaw cycles. Opiate concentrations were decreased in all conditions, but the most unstable was 6‐acetyl‐morphine. The addition of NaF as preservative improved the stability of opiates at all conditions studied, whereas the type of anticoagulant did not affect the stability of opiates. It was concluded that blood samples should be stored at ?20^°C in glass tubes containing oxalate and NaF for maximum stability.     

血液中乙醇保存稳定性研究

目的确定血液中乙醇最佳保存条件,探讨影响血液中乙醇含量稳定性的主要因素。方法对血液保存的温度(-20、4、20℃)、防腐剂(NaF、无防腐剂、Na2O2)、储存容器中空气所占比例(0%、25%、50%)和血醇质量浓度(0.2、0.8、2.0mg/mL)四个因素采用正交试验L9(34)方法分组,样本采用顶空气相色谱法进行测定,测定结果采用方差分析进行讨论。结果在20℃保存且不加入防腐剂的两组样本中血醇浓度变化明显,其余变化不明显。结论血液样本在4℃、储存容器中空气比例为50%和加防腐剂(NaF)的条件下保存,稳定性最佳;四个影响因素中温度为影响血液中乙醇含量稳定性的主要因素。     

Instability of pancuronium in postmortem blood and liver taken after a fatal intramuscular Pavulon injection

The present study was designed to determine the stability of pancuronium in postmortem blood and liver during storage. Results were obtained using the method by Kerskes et al. [C.H.M. Kerskes, K.J. Lusthof, P.G.M. Zweipfenning, J.P. Franke, The detection and identification of quaternary nitrogen muscle relaxants in biological fluids and tissues by ion-trap LC-ESI-MS, J. Anal. Toxicol. 26 (2002) 29-34.], modified and validated in our laboratory. Target analytes were isolated after enzymatic hydrolysis followed by solid phase extraction (BondElut C18 column). Internal standardisation was carried out using laudanosine and the target ions were monitored by LC-ESI-MS (monitoring ions m/z 358 for IS and 286 for pancuronium). Materials were taken from a 46-year-old woman, who had been found dead. A syringe (2 ml) and an empty ampoule of Pavulon (4 mg/2 mL) were found in her hand. The residual volume of fluid in the syringe was 0.7 ml. An autopsy was performed six days after death. It revealed a needle mark on the left thigh. Postmortem materials (muscle from the injection site, blood and liver) and the syringe with fluid were stored for four months in a freezer at -20 degrees C. The initial pancuronium concentrations were 81 ng/mL in blood and 532 ng/g in liver. The analyte was stable when stored at -20 degrees C in blood even up to seven months. In liver samples its concentrations were variable. Pancuronium in blood stored at 20 degrees C underwent degradation very rapidly. After three months of storage these blood samples had concentrations not greater about 10% of the initial value. The degradation patterns of pancuronium depended on temperature and the biological matrix.     

Concentrations of cocaine and its major metabolite benzoylecgonine in blood samples from apprehended drivers in Sweden

Cocaine and its major metabolite benzoylecgonine (BZE) were determined in blood samples from people arrested in Sweden for driving under the influence of drugs (DUID) over a 5-year period (2000-2004). Venous blood or urine if available, was subjected to a broad toxicological screening analysis for cannabis, cocaine metabolite, amphetamines, opiates and the major benzodiazepines. Verification and quantitative analysis of cocaine and BZE in blood was done by gas chromatography-mass spectrometry (GC-MS) at limits of quantitation (LOQ) of 0.02mg/L for both substances. Over the study period 26,567 blood samples were analyzed and cocaine and/or BZE were verified in 795 cases (3%). The motorists using cocaine were predominantly men (>96%) with an average age of 28.3+/-7.1 years (+/-standard deviation, S.D.). The concentration of cocaine was below LOQ in 574 cases although BZE was determined at mean, median and highest concentrations of 0.19mg/L, 0.12mg/L and 1.3mg/L, respectively. In 221 cases, cocaine and BZE were together in the blood samples at mean and (median) concentrations of 0.076mg/L (0.05mg/L) and 0.859mg/L (0.70mg/L), respectively. The concentrations of BZE were always higher than the parent drug; mean BZE/cocaine ratio 14.2 (median 10.9) range 1-55. Cocaine and BZE were the only psychoactive substances reported in N=61 cases at mean (median) and highest concentrations of 0.095 (0.07) and 0.5mg/L for cocaine and 1.01 (0.70) and 3.1mg/L for BZE. Typical signs of drug influence noted by the arresting police officers included bloodshot and glossy eyes, agitation, difficulty in sitting still and incoherent speech.     

Stability of diazepam in blood samples at different storage conditions and in the presence of alcohol

Diazepam is one of the mostly used benzodiazepines and it is frequently analyzed in different biological samples, especially blood samples. The diazepam stability in the sample matrices is an important factor regarding reliable data obtaining. The storage is the main factor determining the stability of diazepam in blood samples and it is the object of the study presented. Remaining diazepam amount in spiked whole blood and plasma samples were tested at different storage temperatures, in the absence or presence of sodium fluoride as stabilizer as well as the influence of ethanol on diazepam stability was evaluated. The results of the study indicated that the temperature is the main storage factor affecting diazepam stability. In the fluoride stabilized blood samples the amount of diazepam decreases up to 85% of initial level when stored at -20° C for the period of testing (12 weeks). The presence of low (0.5 g/L) or high (3g/L) ethanol concentrations influences the stability of diazepam at -20 °C. In whole blood samples, the combination of sodium fluoride and ethanol decreases additionally (15-25%) the concentration of the analyte. Freeze-thaw experiments of whole blood samples show about 5-9% decrease in diazepam concentration after the first cycle. The freeze-thaw experiments on plasma samples, containing ethanol and/or fluoride show insignificant decreases of analyte concentration. Further experiments on benzodiazepines stability at different storage conditions or in combination of different factors should be undertaken in forensic toxicology to ensure the data quality, their reliability and reproducibility.     

Tissue disposition of cocaine in man: a report of five fatal poisonings

The disposition of cocaine in five cases of fatal poisoning are presented. The highest concentrations of cocaine were found in urine, kidney, spleen, brain, lung and skeletal muscle. Cocaine concentrations in these organs far exceeded those in blood. Cocaine was detected in all other specimens tested including: bile, heart, liver, vitreous and adipose tissue. These results are in agreement with limited, previously reported, tissue data, and indicate that when urine is not available, kidney, spleen, brain and/or lung should be the specimen of choice for cocaine detection.     

LC-MS-MS analysis of buprenorphine and norbuprenorphine in whole blood from suspected drug users

A liquid chromatography tandem mass spectrometry method is described for the analysis of buprenorphine and norbuprenorphine in whole blood. Linearity was achieved between 0.2-5 ng/g for buprenorphine and 0.5-5 ng/g for norbuprenorphine. Stability studies on spiked whole blood and an authentic sample showed no degradation of buprenorphine- and norbuprenorphine-glucuronide to their respective aglycones. Buprenorphine and norbuprenorphine showed some degradation when stored at 4°C for three weeks, but was stable when stored at -20°C for 4 weeks. The method was applied to forensic cases of driving under the influence of drugs (DUID) and petty drug offences (PDO) during 2007-2009. Out of 2459 cases analyzed, 322 were positive for both buprenorphine and norbuprenorphine (13%), 219 for buprenorphine only (9%), and 12 for norbuprenorphine only (0.5%). The mean and median concentrations (N=322) were 1.7 and 1.0 ng/g, respectively, for buprenorphine and norbuprenorphine. The mean and median norbuprenorphine/buprenorphine ratios were 1.5 and 1.1, respectively. There was no significant difference in concentration ratios for DUID and PDO cases (p>0.05). We conclude that the described method for analysis of buprenorphine and norbuprenorphine in whole blood could be used to investigate use or misuse of buprenorphine but that many of the cases presented with very low concentrations of buprenorphine. We also conclude that analysis should be performed within two weeks unless samples are stored frozen prior to analysis.     

Ethanol stability in unpreserved refrigerated antemortem blood

Ethanol stability in preserved antemortem blood has been widely studied since it is a common practice in cases involving suspected impaired driving to collect antemortem blood in evacuated blood tubes containing sodium fluoride. In some situations, antemortem blood is submitted to a forensic laboratory for ethanol analysis in evacuated blood tubes that contain only an anticoagulant. There has been limited research on ethanol stability in antemortem blood stored without a preservative. On two occasions, antemortem blood was collected from five ethanol-free individuals into 6-ml Vacutainer® tubes containing only 10.8 mg potassium EDTA. The blood tubes were spiked with ethanol to approximately either 0.08 or 0.15 g/dl. Dual-FID headspace gas chromatography was used to analyze 58 blood tubes, 29 from each session, for ethanol 1 day after sample collection and again after 1 year of refrigerated storage (~4°C). Statistically significant decreases in ethanol were detected at the 0.05 level of significance. Mean decreases in ethanol after 1 year of storage for the 0.08 and 0.15 g/dl samples were 0.013 and 0.010 g/dl, respectively. The mean ethanol decrease across all tubes was 0.012 g/dl. The range of decreases for the 58 blood tubes was 0.003–0.018 g/dl. The mean ethanol decreases measured in this unpreserved antemortem blood are comparable in magnitude to those previously observed in antemortem blood containing sodium fluoride after 1 year of refrigerated storage. Ethanol did not increase in the antemortem blood samples despite the absence of sodium fluoride.     

Mitochondrial DNA and STR analyses of maggot crop contents: effect of specimen preservation technique

DNA analysis of maggot crop contents can be used to identify a missing body or aid entomologists with interpreting evidence used for PMI estimations. Entomological evidence is often collected and preserved to keep identifiable external features intact. The preservation methods currently in use may not be suitable for preserving DNA in the maggot crop for later analysis. In this study, carrion maggots raised on human tissue were preserved under the following 8 preservation conditions: no fluid at -70 degrees C, no fluid at 4 degrees C, no fluid at 24 degrees C, 70% ethanol at 4 degrees C, 70% ethanol at 24 degrees C, 95% ethanol at 24 degrees C, Kahle's solution at 24 degrees C and formaldehyde at 24 degrees C. Maggots were dissected following 2 weeks, 8 weeks and 6 months of preservation. The maggot crops were extracted, human DNA was quantitated, and an attempt was made at amplifying mitochondrial DNA (mtDNA) and short tandem repeat (STR) loci. Both mtDNA and STRs were successfully amplified from maggots stored in ethanol or without any preservation fluid. Formalin-containing preservation solutions reduced the recovery of DNA. The best results were observed from maggots stored without any preservation fluid at -70 degrees C.     

In vitro production of GHB in blood and serum samples under various storage conditions

The in vitro production of GHB was observed in freshly collected, untreated whole blood samples using glass BD-Vacutainers and polypropylene S-monovettes. GHB concentrations were determined daily over a period of one week and after 3, 6 and 9 weeks again. Furthermore, the GHB concentration in 40 untreated random whole blood samples stored at 4°C for a longer period of time (10 samples 12 month, 10 samples 24 month and 20 samples 36 month) was also determined. For comparison, the in vitro production of GHB in freshly collected and prepared serum samples was observed. GHB serum concentrations were determined three times over a period of one week and once again after six weeks. Sample preparation was performed by means of methanolic extraction following the precipitation of whole blood and serum samples. A methanolic standard calibration was done in a low range of 0.005-0.1 μg/mL (LOD: 0.004, LLOQ: 0.013). For quantification a spiked blood bank serum with a determined GHB concentration of 0.09 μg/mL was used. Corrected calibrations in the range of 0.09-5.09 μg/mL were used (LOD: 0.08 μg/mL, LLOQ: 0.30 μg/mL), recovery: 91.3% (high level: 4.09 μg/mL) 50.5% (low level: 0.19 μg/mL). RESULTS: Relevant elevation of GHB was observed in all whole blood samples stored in liquid form (4°C or room temperature). In two of the 40 whole blood samples stored over a longer period of time at 4°C, GHB concentrations in the range of 13 μg/mL were even determined. These findings constitute grounds for caution. Even a GHB cut-off level of 5 μg/mL cannot be considered as "absolutely positive" proof of a case of exogenous administration, at least in untreated liquid blood samples in long time storage. However, no significant elevations of GHB were otherwise observed in any of the serum samples independently of storage temperature nor in the whole blood samples that were frozen for storage. CONCLUSIONS: The results suggest that the cut-off for exogenous GHB of 5 μg/mL could be lowered significantly, with the consequence of winning valuable time for the potential victim, but only if serum is collected for GHB determination or if the whole blood sample is frozen immediately after collection and the procedure well documented.     

The influence of storage temperature and chemical preservation on the stability of succinylcholine in canine tissue

Succinylcholine (SCh) has been detected six months postmortem in liver, kidney, and injection site muscle of rats given 10 to 200 mg/kg by intramuscular injection. SCh stability was studied in canine tissue to evaluate three storage temperatures and two chemical preservatives at three time periods after injection. Nine mongrel dogs weighing 17.2 to 28 kg were divided equally into three groups and administered either 0.5, 1.0, or 5.0 mg SCh/kg intravenously into the cephalic vein. Liver, kidney, and gastrocnemius muscle were removed 90 min post-injection and divided into twelve portions. Each portion was treated with embalming fluid, physostigmine, the combination (50/50), or nothing. Chemically treated tissues and nontreated tissues were then stored at either 27, 5, or -20 degrees C for a period of up to forty days. Tissue portions were analyzed using ion-pair extraction, chemical demethylation, and gas chromatography with nitrogen phosphorous detection. Stability of SCh was greatest for samples stored at -20 degrees C and preserved with the combination of embalming fluid plus physostigmine. Kidney concentrations of SCh were significantly higher than those in liver or muscle at all doses. SCh was detected 24 h post-injection in all cases. By 40 days, only trace amounts of SCh, if any, could be detected in samples stored at room temperature with no chemical preservatives.     

The Stability of 4-Chloromethcathinone in Blood and Vitreous Humor

We present results of our study on the stability of 4-chloromethcathinone (4-CMC) in authentic postmortem peripheral blood and vitreous humor samples. The stability of 4-CMC was determined in postmortem blood samples (for a period of 90 days) and vitreous humor (30 days) at three different temperatures: −15°C, +4°C, and + 23°C. The analyses were carried out using ultra-high-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (UHPLC-QqQ-MS/MS). In both materials, the lowest 4-CMC stability was demonstrated at room temperature. The blood samples stored in a freezer (−15°C) showed stability for the entire study period (90 days), while in the case of the vitreous humor sample stored at the same temperature the concentration of the substance decreased by 53% after 30 days. The study carried out in authentic postmortem blood and vitreous humor samples confirms the previous reports of 4-CMC instability in biological material. Authors suggest that the biological material should be stored frozen until analyses are carried out as soon as possible after collection of the material.     

Detection of ABH blood group antigens in the saliva of Koreans and their stability according to storage of saliva samples

The purpose of the present study was to identify salivary molecules carrying the ABH blood group antigens in Koreans and to investigate the changes in these antigens according to processing and storage of saliva samples. Secretor or non-secretor phenotypes and salivary components carrying the ABH antigens were identified in 90 subjects, 30 subjects in each ABO blood group, by SDS-PAGE and immunoblotting. Saliva samples were then obtained from 12 secretors-two males and two females in each ABO blood group and aliquots of both fresh saliva samples and their supernatants after centrifugation were stored at room temperature, 4, -20 and -70 degrees C. The same experiments were performed after 1, 3 and 6 months to investigate changes in the blood group antigens. In all 68 secretors, high-molecular-weight salivary mucin (MG1) was found to be the primary carrier of the ABH antigens. A salivary component of approximately 80 kDa also carried H antigen in seven saliva samples of 22 blood type O secretors. The blood group antigens were better detected in centrifuged samples. In saliva samples preserved at room temperature and 4 degrees C, the blood group antigens were either not detected or detected as degraded molecules. No change was found in the blood group antigens in saliva samples preserved at -20 and -70 degrees C for 6 months.     

Site-dependent postmortem changes in blood cocaine concentrations

When a forensic toxicologist interprets postmortem blood cocaine findings he usually must make assumptions regarding perimortem drug concentrations. In-vitro studies have shown that cocaine rapidly hydrolyzes in unpreserved blood, particularly at elevated temperatures. However, other studies have demonstrated site-dependent postmortem release of some drugs from tissue stores accompanied by increases in drug concentrations in the blood. This study was undertaken to investigate whether blood cocaine concentrations change in the body during the postmortem interval and, if so, to measure the direction and magnitude of the changes. In medical examiner cases in which scene investigation suggested that the decreased was a cocaine user, blood samples were collected as soon after death as possible. At autopsy, a second set of samples was collected. Analysis of paired samples by gas chromatography/mass spectrometry (GC/MS) revealed dramatic differences in the cocaine concentration. The magnitude and direction of the change appears to be site dependent. Usually, but not invariably, cocaine concentration in subclavian vein blood decreases while that in heart, aorta, and femoral vein blood increases during the interval between death and autopsy. The findings emphasize the danger inherent in attempting to estimate the concentration of cocaine in blood at the time of death from postmortem data.