A rapid and sensitive method for the determination of paraquat in plasma and urine by thin-layer chromatography with flame ionization detection.

A new method for the determination of paraquat in biological fluids has been developed. It involves thin-layer chromatography with flame ionization detection (TLC/FID) and simple solid-phase extraction with a disposable octadecylsilane column. This procedure allows direct loading of the samples on the disposable column. When Chromarod SII is used as the stationary phase and methanol-2N hydrochloric acid (2:3, v/v) as the mobile phase, recovery levels of paraquat in spiked materials are from 87.5 to 98.0%. This method can be used for samples of paraquat at levels as low as 50 ng.

Detection of tetrodotoxin in autopsy material by gas chromatography.

A gas chromatographic method for the detection of tetrodotoxin in autopsy material is described. The derivative (2-amino-6-hydroxymethyl-8-hydroxyquinazoline, C9-base), which was obtained from tetrodotoxin by alkali treatment, was finally detected by gas chromatography. The mass spectra of the trimethysilylated ( TMS) C9-base are presented together with the result of a gas chromatographic investigation of 8 cases of fatal intoxication.

Gas chromatographic and gas chromatographic-mass spectrometric determination of gasoline in a case of gasoline vapor and alcohol poisoning.

A case of fatal poisoning due to the combined effect of alcohol and gasoline following an automobile accident is described. Toxicological analyses by means of gas chromatography and gas chromatography-mass spectrometry permitted the identification and quantitation of alcohol and several hydrocarbons in the heart blood and in the gas in the lung. Great variation was found in the estimates of blood gasoline concentration, depending on which of six constituents of gasoline was chosen for quantitation. The cause of this variation is discussed, together with the possible mechanisms leading to death.

[Analysis of digital subtraction angiography for estimating flow reserve in critical coronary artery stenosis].

To assess the accuracy of digital subtraction angiography in evaluating coronary flow reserve in cases with critical coronary artery stenosis, time-density curves were obtained from digital subtraction coronary angiograms in the myocardial region of interest. Time to peak contrast (TPC) and time constant of the washout exponential curve (T) were measured in 14 patients with stable effort angina pectoris and critical one vessel lesion before and after percutaneous transluminal coronary angioplasty (PTCA). All patients had normal left ventricular ejection fraction (59 +/- 7%) and 201T1 myocardial images at rest. The values of TPC and T were significantly shortened from 5.4 +/- 1.3 to 4.5 +/- 1.0 sec (p less than 0.02) and from 10.9 +/- 3.8 to 5.3 +/- 1.3 sec (p less than 0.001) after PTCA, respectively. However, in 9 patients TPC values were approximately the same before and after PTCA. In five experimental dogs with critical circumflex coronary artery stenosis, coronary flow (CF; Doppler flowmeter) and systolic thickening of the posterior wall (by sonomicrometry) at rest did not differ from those of the controls. However, contrast media-induced reactive hyperemia was markedly attenuated, accompanied by a significant increase in T (7.7 +/- 4.5 vs 15.8 +/- 10.9 sec, p less than 0.01) and totally unchanged TPC (both 6.8 sec). With simultaneous tracings of CF and time-density curves, TPC and washout phases corresponded with contrast-induced transient CF reduction and hyperemic phases, respectively. We concluded that T may be more sensitive for estimating CF maintained nearly normal, e.g., in patients with stable effort angina pectoris having normal left ventricular wall motion at rest.