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On the basis of the Townsend equation for the gas amplified current and of the Dutton—Powell equation for the enhancement of the primary ionization coefficient in gas mixtures due to the Penning effect, a mathematical model of the chromatographic helium detector is proposed. Because both calculations of the relative current increase for E/p = 4, 5 and 6 V/em·torr and actual measurements lead to linear calibration graphs for the sample calibrations at the parts per million level, a simplified and linearized relationship was developed, although further experimental confirmation is needed. The suggestion is made that the derived equation will make possible measurements of the 0 number of metastable states produced per electron per centimetre of drift in an electric field, and the cross-sections for the Penning effect. The rate constants for Penning ionization by triplet metastable atoms of helium for hydrogen sulphide and ethylene were evaluated but the results are of a relative character. The shortcomings of the model are considered: the lack of explanation of negative peaks, the role of specially added admixtures to the carrier gas, and no account of recombination phenomena are the most important. A brief scheme of necessary investigations is outlined.

Fluorigenic labelling techniques have been used for several years in conjunction with thin-layer chromatography, and are now being used also to good advantage in high-speed liquid chromatography. In this work, reagents such as 4-chloro-7-nitrobenzo-2,1,3-oxadiazole, dansyl chloride and dansyl-hydrazine were used for the fluorigenic labelling of carbamates, ureas, organophosphorous compounds, aliphatic amines, aldehydes, ketones, biphenyls and some compounds of pharmaceutical interest. The labelling reactions and the nature of derivatives are discussed, together with the column liquid chromatography properties of these derivatives in both liquid—liquid and solid—liquid modes. Detection limits obtained for most compounds with a new fluorimetric detection device range between 1 and 10 ng per 4-μl injection volume. The method is suitable for quantitative analysis, with a reproducibility of ca. 3% relative standard deviation. Linear calibration plots for peak area or peak height versus concentration were observed up to 600 ng per injection. The method has been applied successfully to the environmental sample analysis of pesticides in water, soil and vegetables without the necessity for a preliminary clean-up. The method is comparable in sensitivity and accuracy to gas chromatography. The advantages of this method can be summarized as follows: improved detection properties, such as better sensitivity, flow-insensitive detection mode and higher specificity; lowering of polarity of the compounds, hence greater ease of separation; suitable for automation and routine analysis; the range of possible applications is limited only by the available labelling reagents and separation procedures.

Three methods are described which allow the quantitative analysis of hydrogen in gaseous mixtures, when helium is the carrier gas. These methods are respectively based on the simultaneous calibration with air, the simultaneous calibration with hydrogen and the determination of the correction factor curve. All the methods can be applied to other carrier gases and samples.

A rapid gas chromatographic method has been developed for determining the composition of the organic phase of the continuous TNT process. The method provides analyses for isomers of mono-, di-, and trinitrotoluenens in samples from nitration phases and for residual dinitrotoluenes and asymmetrical trinitrotoluenes from the TNT purification process and in the final product. The column used for separation was 10% UC-W98 silicone rubber on 80–100 Diatoport-S. Detector response factors were determined and used to calculate relative percent components to eliminate time-consuming calibration and achieve better reproducibility.

The support phase has been shown to influence values for relative retention by either the adsorption of solute moleculs or the adsorption of the hydroxyl groups of certain polar liquid phases. Also, it has been deduced that appropriately shaped molecules, which have a low affinity for the solvent, can be selectively retained by trapping in the micro pores in the surface of certain supports, in particular teflon. On the basis of these observations it has been found that silanized Chromosorb G is the least adsorptive of a wide range of commercially available support materials.

The pulse chromatograph technique was applied to the measurement of adsorption isotherms in systems that involve large adsorbed amounts and some “irreversible” adsorption. The assumptions necessary for successful measurement were verified. A method that permits direct calibration on strongly sorbing sorbent was developed. The adsorption isotherms of aliphatic amines on cobalt and alumina were measured over a wide temperature range and the isosteric heats of adsorption were calculated.

The ideal detector for quantitative analysis by gas chromatography would need neither calibration nor the application of integration procedures to a differential chromatogram. This paper describes the experimental realization of a detector possessing these two desirable characteristics. The “Brunel” mass integral detector yields an integral chromatogram in which the absolute masses of the sample components are directly recorded as step-heights.

Multicomponent mixtures of acetone, methanol, propanol and butanol were analysed using calibration mixtures, constant area factors and a linear relationship. The latter is simple to apply and, compared with the former methods, gives satisfactory accuracy.

The mass detector has been usef for the analysis of a wide range of materials embracing low boiling and high boiling liquids. Some low boiling materials were quantitatively detected without calibration by operating the detector below room temperature. The quantitative analyses of a wide variety of mixtures of normal and high boiling liquids were carried out and satisfactory results obtained without the necessity for calibration. The response of the detector toward gases has been studied.

The mass detector was used to confirm the predictability of response of the Martin gas density balance, to calibrate a katharometer, and to measure limits of detection. The mass detector was operated in parallel with two destructive detectors, the flame thermocouple and flame ionisation detectors, and response curves were constructed for several different compounds.

A technique for the quantitation of flat-bed chromatograms or electropherograms involving the minimum exposure time necessary for a spot just not to appear on a photograph has been developed. For calibration purposes the minimum exposure time is plotted against the amount of substance spotted. The amount of a substance present in an unknown spot is determined from the minimum exposure time. The procedure is inexpensive, simple and particularly suitable for occasional quantitations.

A method for the detection and recording of component bands has been described. It was found to be sufficiently general to insure its applicability to a wide variety of solvent-solute systems, and since it senses the column effluent it is independent of the type of chromatographic column used. It appears to be readily adaptable to the quantitative estimation of non-volatile solute bands for which it is based on essentially a colligative property, and it appears applicable, with specific calibration, to volatile solute bands as well.

Nine European laboratories have taken part in a joint exercise in which two samples, one containing about 98% benzene and the other 90% toluene, were analysed, using chromatographic equipment available to each laboratory. For each sample, a known quantity of a specified internal standard was used and the composition of the samples was calculated from calibration data based on (I) peak height, (2) peak height X retention distance, (3) peak height x width of peak at half peak height. The precision of the results is least for method (3), but method (I) is preferred because it is the simpliest. The results for the toluene sample were less precise than those for the benzene sample. Further work is in progress.

The reproducibility of the photometric evaluation of spots on thin-layer chromatograms for the determination of the concentration of substances was investigated. The remission of some U.V.-absorbing test substances was measured at a wavelength of 254 nm. The deviation of the remission value on one plate, on plates of the same series and on plates of different series was determined. A calibration curve obtained for one series of measurements can be used for later measurements if calibration values at two different concentrations are determined again. When using plates that have not been specially selected, the relative standard deviation with which the concentration can then be determined from the remission value—at not too low concentrations—is on an average 10%. In the cases investigated, it was found that for low concentrations measurement of the remission value of the centre of the spot gives the most accurate results, while for medium concentrations aboutthe same accuracy is obtained when the remission values over the whole spot are averaged. The thickness and density of the silica gel layer primarily affect the ascension rate of the solvent front and consequently the spread of the spot in the direction of flow. Only a very slight influence of the thickness of the layer on the remission value could be detected, since several effects compensate each other.

It is usually difficult to obtain narrow molecular weight distribution samples of a given polymer for calibrating the gel permeation chromatographic instruments in the conventional way. The literature reports several methods which have been used to obtain instrument calibrations with samples of broad distribution polymer. However, these methods generally must assume a linear calibration of the logarithm of molecular weight versus elution volume. This assumption may lead to significant errors in precise molecular weight distribution computations. It is possible to avoid this assumption by making use of the universal calibration curve proposed by Benoit without the necessity of defining this curve by any mathematical function. A number of methods have been developed for combining the universal calibration curve with measurable parameters of the polymeric material (such as intrinsic viscosity, number average molecular weight and weight average molecular weight) to calculate molecular weight distributions. Results will be reported on a careful evaluation of the accuracy and reproducibility of several of these methods.

From a series of international testing programmes, the precision attainable in the analyses of hydrocarbon mixtures with components present in the range 0.001–30% has been established. Only the minimum standardization of procedure and equipment has been demanded in these programmes. Conclusions are drawn on the relative precision of katharometers and flame ionization detectors, methods of chromatogram assessment and methods of calibration. Recommendations are made on procedures necessary to minimize errors in gas—liquid chromatographic techniques without complete standardization of equipment and procedure.

A method for calibration of tightly cross-linked gel filtration chromatography media based on the elution characteristics of a series of selected sugars and alcohols is described. The elution position of all molecules is determined by the column effluent refractive index change and is correlated with both the molecular weight and the unhydrated radius estimated from molecular models.

The flame-ionisation detector has a linear reponse over a range of four orders of concentration, i.e. 10 −0 to 10 −10 g/ml, and this range could probably be extended to six orders by employing suitable experimental conditions. The detector response is independent of the applied voltage, over the range of 25—150 V, and has a sensitivity of approximately 10 −11 g/ml. The macro-argon ionisation detector has a linear response over a small concentration range at one particular voltage, the value of which may vary from one substances to another. Inclusion of a linearising resistance does not result in a linear response. Calibration of the macro-argon detector is essential for accurate quantitative analysis due to the variability of the response index. The sensitivity of the detector is about 10 −13 g/ml.