Two fatal intoxication cases with imidacloprid: LC/MS analysis.

Imidacloprid [1-(6-chloro-3pyridylmethyl)-N-nitroimidazolidin-2-ylideneamine] is a new and potent nitromethylene insecticide with high insecticidal activity at very low application rates. It is the first highly effective insecticide that, like nicotine, acts on the nervous system, causing blockage of postsynaptic nicotinergic acetylcholine receptors. Two fatal cases with this insecticide in two male individuals, of 33 and 66 years old, are presented. An LC/MS with electrospray method for measuring imidacloprid and its metabolites in post-mortem samples is described. In the chromatographic separation, a reverse-phase column XTerra MS C18 (2.1mm i.d.x 150 mm, 5 microm) was used and the mobile phase composed with acetonitrile and 0.1% formic acid (15:85), at a 0.25 mL/min flow rate. Samples were prepared with a liquid-liquid extraction procedure with dichloromethane. Calibration curves for imidacloprid in blood and urine samples were linear from 0.2 to 15 microg/mL. The mean recovery was 86% with a coefficient of variation of +/-5.9%. The detection limit was 0.002 microg/mL. Quantitative results were obtained for all post-mortem matrices available of the two fatal cases: blood, urine, stomach contents, lung, liver and kidney. The imidacloprid blood concentrations found in two-cases were 12.5 and 2.05 microg/mL. The authors validated a method to detect and quantify imidacloprid in post-mortem samples, and to our knowledge for the first time a post-mortem tissue distribution was performed on various samples for this insecticide.

Pesticide intoxications in the Centre of Portugal: three years analysis.

Pesticides are used in most countries around the world to protect agricultural and horticultural crops against damage. Poisoning by these toxicant agents occurs as a result of misuse or accidental exposure, and also by oral ingestion (voluntary or not). In Portugal, pesticide intoxications are still a cause of death, found in a considerable number of cases. The authors retrospectively examined the cases of pesticide poisoning in the Centre of Portugal, from autopsies performed in the Forensic Pathology Service of Coimbra's Delegation of the National Institute of Legal Medicine (NILM) and from other autopsies carried out in the Centre of Portugal, as well as some samples taken in hospitals in cases of suspected intoxication. In this study, the positive cases have been especially studied, in order to identify the pesticide used, as well as the etiology. The frequency of intoxications and its distribution by sex and age were also analyzed. Between January 2000 and December 2002, the Forensic Toxicology Laboratory received 639 pesticide analysis requests. In 2000, in a total of 149 analysis requests, 30 cases were positive, 63.3% from male individuals and 36.7% from female. In 2001, the analysis requests increased to 240 as well as the positive cases (43), 74.4% from male individuals and 25.6% from female and in 2002, the total cases analyzed also increased to 250, with 38 positive (73.6% from male individuals and 26.4% from female). Among the pesticides, organophosphorus insecticides still constitute the most important class detected in forensic intoxications, representing 63% of the total positive cases, followed by herbicides, with 33% of the positive results. Quinalphos is the most important organophosphorus insecticide, present in 32 of the 111 positive cases, followed by the herbicide paraquat, detected in 31 cases. The study emphasizes the increasing number of pesticide analyses, particularly relevant for the organophosphorus compounds and herbicides. Intoxication suspicion, accidental or voluntary, seems to be the most common cause of the incidents, for which analyses are requested, but it is also evident that the putative cause is unknown in a large number of cases. Therefore, more stringent legislation and enforcement regarding the sale and distribution of these toxic substances are needed.

Forensic intoxication with clobazam: HPLC/DAD/MSD analysis.

Clobazam (Castillium, Urbanil), a benzodiazepine often used as an anxiolytic and in the treatment of epilepsy, is considered a relatively safe drug. The authors present a fatal case with a 49-year-old female, found dead at home. She had been undergoing psychiatric treatment and was a chronic alcoholic. The autopsy findings were unremarkable, except for multivisceral congestion, steatosis and a small piece of a plastic blister pack in the stomach. Bronchopneumonia, bronchitis and bronchiolitis were also diagnosed. Anhigh-performance liquid chromatography (HPLC)/diode array detector (DAD)/mass spectrometry detection (MSD) with electrospray method was developed in order to detect, confirm and quantify clobazam in the post-mortem samples. In the chromatographic separation, a reversed-phase column C18 (2.1 x 150 mm, 3.5 microm) was used with a mobile phase of methanol and water, at a 0.25 ml/min flow rate. Carbonate buffer (pH 10.5) and 20 microl of prazepam (100 microg/ml) as internal standard were added to the samples. A simple and reliable liquid-liquid extraction method for the determination of clobazam in post-mortem samples was described. Calibration curves for clobazam were performed in blood, achieving linearity between 0.01 and 10 microg/ml and a detection limit of 1.0 ng/ml. The clobazam concentration found in post-mortem blood was 3.9 microg/ml, higher than the reported therapeutic concentration (0.1-0.4 microg/ml). The simultaneous acquisition by photodiode array detection and mass spectrometry detection results allowed benzodiazepines to be identified with sufficient certainty. An examination of all the available information suggested that death resulted from respiratory depression due to clobazam toxicity.

Cannabis and driving: the use of LC-MS to detect delta9-tetrahydrocannabinol (delta9-THC) in oral fluid samples.

Cannabis is the most widely used illicit drug in the world. There is strong evidence from performance studies that delta9-THC has significant effects on the cognitive and psychomotor tasks associated with driving. New, easy and sensitive methods to detect impaired drivers are needed. Therefore, it is necessary the use of alternative biological samples which may be accurate, precise and with trustful interpretation results. This article presents an LC-MS methodology for detecting delta9-tetrahydrocannabinol (delta9-THC) in oral fluid samples. The mean recovery was 79%, coefficients of variations were between 2.9% and 6.9% and the limits of detection (LOD) and quantitation (LOQ) were 1.0 ng/ml and 2.0 ng/ml, respectively. The method is sensitive, accurate and reproducible and may be utilized in ongoing controlled cannabinoid administration studies and in roadside studies and thus, important for the fields of forensic toxicology.

Aldicarb poisoning: one case report.

The carbamate aldicarb (Temik) is a highly toxic (LD50 = 0.9 mg/kg oral in rats) insecticide often used in agriculture. The authors present a fatal intoxication case with aldicarb, in a 24-year-old male, under police custody in the island of S. Tome and Prince (STP), in Africa. He was found 3 h after his arrest, lying on the floor of his cell, unconscious, frothing at the mouth, and entered into the hospital already dead. Aldicarb analysis was carried out by high-performance liquid chromatography, with a post-column derivatization system (with o-phthaldialdehyde and 2-mercaptoethanol, under alkaline conditions at 80 degrees C) with fluorescence detection at lambda(ex)= 339 nm and lambda(em) = 445 nm. The toxicological analysis revealed toxic concentrations of aldicarb in the post-mortem samples: blood (6.2 microg/ml), stomach (48.9 microg/g), liver (0.80 microg/g), kidney (8.10 microg/g), heart (6.70 microg/g) and urine (17.50 microg/ml). It was also detected to be the same substance in a grey granulate powder supplied by criminal authorities of that country, as a probable substance ingested by the victim. The toxicological analysis results, the autopsy findings and the information given, allowed us to conclude that death occurred due to an aldicarb acute intoxication. Although the case suggested a suicide, particularly based on the known information and on the high aldicarb concentration found in the stomach, it was not possible to indicate precisely its etiology (suicide or homicide).