Gunnar Widmark

Absorption of Ocular Timolol

SummaryThe absorption of timolol after topical administration to the eye was studied in 11 healthy volunteers and in 5 patients with bilateral open angle glaucoma. The volunteers received 2 drops of 0.5% timolol ophthalmic solution in each eye, equivalent to 0.8mg of timolol maleate. Overflow was absorbed by paper tissue. The patients received the same dose twice daily for 2 weeks and were then investigated. In the paper tissue, 12 to 88% of the dose administered was recovered. Plasma concentrations were never above 5ng/ml and not always detectable (detection limit 1 to 2ng/ml). However, timolol was absorbed as the drug was found in the urine samples from all volunteers and glaucomatous patients.

Tobacco Chemistry : II. Analysis of the gas phase of tobacco smoke by gas chromatography-mass spectrometry☆

Abstract The gas phase of tobacco smoke was injected, without prior condensation, through a glass injection system onto an efficient glass capillary column maintained at low temperature. Components eluted on temperature programming were studied by means of a mass spectrometer coupled to the column via a low-dead-volume molecule separator. By making use of the separation principle of the phase, thirty-four compounds were identified from their mass spectra.

Qualitative determination of polyaromatic hydrocarbons in the air near gas-works retorts

Abstract An extract of air particulates from a gas-works was separated by two-dimensional thin-layer chromatography. Thirty-five different fractions could be readily observed. Retention values, UV-visible absorption spectra and mass spectra of 14 of the fractions were all very close to corresponding experimental data of standard polyaromatic hydrocarbons. For nonhydrogenated polyaromatic hydrocarbons, a linear relationship was observed between molecular weight and retention value in the first dimension of the thin-layer chromatographic system used.

Separation of fresh tobacco smoke on a packed polar gas chromatographic column prior to on-line analysis by gas chromatography-mass spectrometry using a non-polar capillary column.

Gaseous samples of fresh tobacco smoke were injected on to a packed polar column (2,2-oxydipropionitrile) in all-glass chromatographic system. With the aid of a warm syringe, selected fractions were withdrawn from the bottom of the electron capture detector of the packed column for further injection into an efficient non-polar glass capillary column (SF-96), connectable on-line to a mass spectrometer. The method has permitted the separation and identification of some polar and non-polar components of tobacco smoke, which gave previously mixed, broad, tailing peaks when the smoke was injected directly into a non-polar capillary column.

Collection and Determination of Mercury in Air

Abstract A method has been developed for the determination of low concentrations of mercury in air (nanograms/m3), i.e. in the range of the believed natural levels of mercury in the atmosphere (20 ng/m3). Mercury vapour has been collected from up to 2001 of air in glass tubes containing thin films of gold on sieved ceramic powder. In the laboratory theabsorbed mercury was then released into a quartz-window cell by heating the tube in an oven at 500°C. In this paper it is demonstrated that, by using extremely thin films of precipitated gold, quantitative recovery is obtained and memory effects, which result from the use of thicker films, are avoided.