Takeaki Nagata

Determination of cyanide and thiocyanate in blood by gas chromatography and gas chromatography-mass spectrometry

We devised a sensitive and simple method for determining cyanide and its major metabolite, thiocyanate, in blood using an extractive alkylation technique. Pentafluorobenzyl bromide was used as the alkylating agent, and tetradecyldimethylbenzylammonium chloride was used as the phase-transfer catalyst. The derivatives obtained were analyzed qualitatively by gas chromatography-mass spectrometry and quantitatively by gas chromatography with an electron-capture detection. The detection limits of cyanide and thiocyanate were 0.01 and 0.003 mumol/ml, respectively, while the gross recovery of both compounds was 80%. The calibration curve was linear over the concentration range from 0.02 to 1.0 mumol/ml for cyanide and from 0.01 to 1.0 mumol/ml for thiocyanate. The accuracy and precision of the method were evaluated, and the coefficients of variation were found to be within 10%. Using the method, the blood levels of two victims who had died from cyanide poisoning were determined.

Sulfide concentrations in postmortem mammalian tissues.

Postmortem changes in sulfide concentrations in body tissues were examined in autopsied rats exposed to hydrogen sulfide concentrations of 550 to 650 ppm, and in nonexposed rats and humans. Analyses were made by gas chromatography, following an extractive alkylation. Sulfide concentrations in the blood, liver, and kidneys of rats increased in both the exposed and nonexposed groups, depending on the lapse of time after death. On the other hand, the lung, brain, and muscle showed little or no change in sulfide concentration with elapse of time after death. The data obtained from human tissues were almost the same as those for rats, except data for blood, in which no or little increase of sulfide was observed.

Extractive Alkylation and Gas Chromatographic Analysis of Sulfide

A sensitive analysis of sulfide in blood was established, using an extractive alkylation technique. Pentafluorobenzyl bromide was used as the alkylating agent, tetradecyldimethylbenzylammonium chloride as the phase-transfer catalyst, and potassium dihydrogenphosphate as the buffer to suppress the formation of sulfide. Mass fragmentography was used to identify the sulfide derivative and gas chromatography with an electron capture detector was used for quantitative determination, with the lowest limit of detection being about 0.01 microgram/g. The blood level of rats exposed to hydrogen sulfide was also determined.

Polychlorinated dibenzo-p-dioxins and related compounds: Correlations of levels in human tissues and in blood

We investigated PCDDs and related compounds levels in human tissue and blood obtained from the general population, and the correlation factor was calculated from the findings. None of the congeners in brain, muscle and lung were correlated except for 2,3,7,8-tetrachlorodibenzo-p-dioxin and octachlorodibenzo-p-dioxin in the brain (p < 0.05). In other tissues, all congeners had relatively good correlations to those in blood (r > 0.707). These congeners detected in blood were at high concentrations in the environment and human body. Therefore, we concluded that these congener levels in the blood might be useful for estimating these congener levels in human tissue.

Simultaneous determination of paraquat and diquat in human tissues by high-performance liquid chromatography

A simple, sensitive, reliable, and economical method for simultaneous determination of paraquat dichloride and diquat dibromide in human biological materials has been developed, using high-performance liquid chromatography. The drugs were extracted from the sample with a Sep-Pak C18 cartridge and applied to a chromatograph with the internal standard, L-tyrosine. Paraquat and diquat were clearly separated on the octadecylsilica column with a mobile phase of 0.5% potassium bromide in 5% methanol solution, containing triethylamine (1 ml/l). The pH of the mobile phase was adjusted to 3-4 with 1.3 M phosphoric acid. Two ultraviolet wavelengths were selected, 256 nm for paraquat as well as the internal standard, and 310 nm for diquat. The calibration curves were linear in the concentration range 0.1-10 micrograms/g, and the lower limit of detection was 0.05 microgram/g. We used this method to examine the concentrations of paraquat and diquat in tissues of an individual at autopsy.

Sensitive and selective determination of bromisovalum by high-performance liquid chromatography/particle beam mass spectrometry

A specific procedure using high-performance liquid chromatography/particle beam mass spectrometry (HPLUPBMS) has facilitated determination of bromisovalum in human plasma and whole blood. Bromisovalum, a sedative and hypnotic, was effectively extracted with SepPak C,, cartridges and selectively determined by HPLUPBMS of EI mode. An originally synthesized 2-bromohexanoylurea served as the internal standard (IS). The calibration curve was linear over the concentration range 0.5-5.0 &g and the lower limit of detection was 0.1 r&g (10 ng at the time of direct injection). This method could be practically applied to detect bromisovalum in the whole blood of an autopsied individual.

Identification of vegetable species in gastric contents using HPLC.

Identification of 16 vegetables, focusing on the influence of digestion in the stomach, was carried out on the basis of the types of flavonoids detected on chromatograms using HPLC. Among the 12 vegetables for which flavonoids were detected, the chromatographic patterns of the flavonoids in digested vegetables were the same as those of the corresponding raw vegetables, making it possible to identify the species of vegetables even after digestion. In our analysis, 5 mg of a freeze-dried sample was found to be an adequate quantity to enable the detection of flavonoids. Brief practical cases are also described.

Identification of species of weeds using high performance liquid chromatography in three crime cases

SummaryStains on clothing from two victims which were later on determined as grass stains, and a blade of dried grass taken from another were examined to identify the sites of crimes. The species of each sample was identified based on the characteristic distribution pattern of flavonoids seen on high performance liquid chromatography. The scene of the crime was clearly traced from the evidential material.ZusammenfassungSpuren an der Bekleidung zweier Opfer, welche sich als Grasspuren herausstellten und ein Halm getrockneten Grases von einem weiteren Kriminalfall wurden mit dem Ziel untersucht, die Orte der Verbrechen zu identifizieren. Die Spezies von jeder Probe wurde durch eine Methode identifiziert, welche auf der charakteristischen Verteilung der Flavonoid-Muster basiert, wie sie in der HPLC nachzuweisen sind. Der Ort des Verbrechens wurde mit Hilfe dieses Beweismaterials klar identifiziert.

Identification of Plant Stains Using High Performance Liquid Chromatography

A study was designed to identify stains derived from plant pigments. Using high performance liquid chromatography (HPLC), 13 species of common weeds were examined, and 12 flavonoids were detected from as low as 100 to 200 μg of dried leaves and from their stains. Identification of plant species could be made, based on the various chromatographic patterns of the flavonoids with different retention indices, using rutin and rhamnetin as the reference standards. A brief practical case of application is described.