M. Dressler

Extraction of trace amounts of organic compounds from water with porous organic polymers

Abstract Determination of organic pollutants in water requires analysis at or below ppb levels. For analysis of such low levels, concentration techniques must be applied. This paper describes a concentration technique based on the sorption of organic compounds on organic porous polymers. The principles of the method, the characteristics and applications of various types of sorbents, the quality requirements for the materials used and the sensitivity of the method are discussed.

Use of olefin-Ag+ complexes for chromatographic separations of higher olefins in liquid—solid systems

Abstract The selectivity effect caused by the formation of olefin—silver ion complexes in systems of propanol—water—AgNO 3 /porous polymers (like Porapak Q) were studied under static and dynamic conditions. Liquid as well as thin-layer chromatographic separations of higher olefins from mixtures with other hydrocarbons are possible with a selectivity equivalent to seven carbon atoms when comparing the chromatographic retention of n -paraffin and n -olefin (heptane, tetradecene) under conditions used.

Direct determination of organic compounds in water using steam-solid chromatography

Abstract A method for analysis of organics in water was developed. The principle is the direct injection of water sample into the gas chromatograph using steam as the carrier gas. The steam developer is described. Analyses of natural polluted water containing hydrocarbons, alcohols and ketones are presented. The method is simple, fast and relatively sensitive to the determination of compounds having a wide range of polarities and a wide range of boiling points. The sensitivity of the method was 10 μg/l for hydrocarbons. The behaviour of the flame ionization detector under conditions of steam-solid chromatography was studied. The detector gives a constant and reproducible response which is, however, lower than that under conventional gas chromatographic conditions. The effect of the hydrogen and steam mobile phase flow-rates upon the detector response differ from those obtained for the flame ionization detector with an inert carrier gas. The other dependences on experimental conditions are similar to those in conventional gas chromatography.

Hydrocarbon and water quenching of the flame photometric detector response

The quenching effect for a flame photometric detector was examined. The range of response quenching was found to be affected by the temperature of the detector. At higher temperatures of the chromatographic column, the quenching effect can also be induced with a stationary phase background. Water does not cause response quenching; on the contrary, it leads to increased detector responses in certain cases. Response quenching due to hydrocarbons and water background does not affect the magnitude of the exponent n.

Response of the alkali flame ionization detector to halogen compounds

Abstract The response of the alkali flame ionization detector to halogen compounds, as well as the effect of the halogen compound structure on the molar response, have been determined using various alkali metals. An increase in response, as compared with the flame ionization detector, occurs with sodium with chloro and bromo compounds and with sodium and potassium in the case of iodo compounds. The molar responses of various monobromo compounds are approximately equal. The response to the chlorobenzenes increases proportionately to the number of chlorine atoms in the molecule.

Effect of detector temperature on flame photometric detector behaviour

Abstract Detector temperature was studied as a parameter affecting the behaviour of the flame photometric detector towards sulphur and phosphorus compounds using 394 and 526 nm filters, respectively. If was found that while the peak heights of sulphur compounds decrease along with increasing temperature of the flame photometric detector, the peak heights of phosphorus compounds increase. At the same time, the exponent n in the dependence of the peak height on the amount of sulphur compounds also decreases. As the detector noise also increases with the detector temperature, the minimum detectable amount of sulphur compounds increases ca. 2.5 times, while that of phosphorus compounds remains approximately the same. The detector temperature also affects the detection selectivity, the P/S ratio increasing six times in one channel over the temperature range 80–160°C. At a constant detector temperature, the selectivity varies with the air flow-rate by ca. two orders of magnitude. It was shown that errors in the quantitative analysis which had not taken into consideration the effect of the detector temperature on the flame photometric detector response can reach values greater than 100%.

Chromatographic behaviour of isomeric compounds on porapak P

Abstract Standard deviations of the gas-chromatographic peaks of different types of organic compounds were determined on different varieties of Porapak. An abnormality in the peaks of the branched alkanes and cycloalkanes was observed on Porapak P and PS columns. The higher was the degree of branching of the compound, the lower was its retention time and the greater was the peak broadening. Olefins, aromatics, alcohols and mercaptants did not show such behaviour. However, sulphides seemed to show a similar effect. The effects of the carrier gas flow-rate, temperature and the coating of the Porapak P on the retention behaviour of isooctane and n -octane were studied.

Column packing for gas chromatography containing immobilized poly(ethylene glycol) stationary phase

SummaryCarbowax 20M poly(ethylene glycol) stationary phase was immobilized on Chromosorb W by cross-linking with pluriisocyanate. The properties of the prepared packing material were investigated. Column efficiencies of 10,960 and 7,510 theoretical plates/meter were obtained for n-pentadecane and 1-heptanol, respectively.

Gas chromatographic properties of immobilized poly(ethylene glycol) stationary phases

Abstract Optimization of the preparation of immobilized poly(ethylene glycol) on Chromosorb W AW was carried out. The optimum concentration ratio of Carbowax 20M and Desmodur L75 in moles lies in the range 1:8 to 1:14. The effect of three different procedures of Chromosorb W AW treatment on the chromatographic properties of the packing material was investigated. Conditioning under a nitrogen stream at 240°C for 4 h appears to be the best. Carbowax 20M immobilized on the support prepared in this way also showed the best stability towards washing with different solvents. A new procedure was used for testing the thermal stability of the stationary phase, which also takes into consideration the extent of the phase immobilization on the support.

Effect of particle treatment of composite filler on its interaction coefficient

Abstract The effect of calcium carbonate treatment on its surface activity was studied by inverse gas chromatography, concentrating on the effect of water on the filler surface, the effect of coating the filler surface with stearic acid and the effect of the particle size of the filler. The surface activity was evaluated by determining the interaction coefficient, I g . Water on the Filler surface decreases the surface activity, especially with untreated calcium carbonate. It also causes a levelling of the difference between the contributions of acid and/or base centres, which can be the cause of incorrect evaluation of their interaction contributions. Consequently, when establishing the filler surface properties, water on the calcium carbonate surface cannot be neglected and thermal conditioning of the filler surface prior to testing is therefore necessary. The dependence of the quality of calcium carbonate surface treatment on the means of adding stearic acid (directly during calcite grinding or from the solution after grinding) was established. The activity of the calcium carbonate surface was found to decrease with increasing particle diameter.