Microdetermination of Carbon and Hydrogen. Modern Industrial Setup

Steyermark, Al

doi:10.1021/i560144a020

Cited by 22 publications

(8 citation statements)

References 7 publications

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“…Tubes removed for inspection after about 100 analyses were in excellent condition, and one tube, in service for about 200 analyses showed fog areas with stains but was otherwise in satisfactory condition. It may' be that a more rapid rate of gas flow is responsible for this difference in behavior from that noted elsewhere (9); Vycor or quartz tubes are essential here because of the higher temperature used.…”

mentioning

confidence: 77%

“…It has been reported (9) that both quartz and Vycor combustion tubes are unsatisfactory in the usual microprocedures, and that failure of Vycor tubes (by cracking) appears to be due to fusion of silver halides and sulfate'into the tube. No such failures were encountered during this work; the limit of service was determined by fogging which occurred slowly over the area heated by' the free flame used under the sample boat.…”

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confidence: 99%

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Semimicrodetermination of Carbon and Hydrogen

Horning¹,

Horning²

1947

Anal. Chem.

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The semimicroproeedure described for the determination of carbon and hydrogen is applicable to samples of 12 to 13 mg., has a high degree of accuracy and reliability in routine work, is as rapid as the micromethod, and may be used under ordinary laboratory conditions. 4 T THE present time the Pregl combustion microprocedure, il with various refinements, is in general use for routine analyses in organic work of all kinds, although in most instances there is no necessity' whatever for the use of a microsample. The general advantage of rapidity of operation with satisfactory accuracy and precision has made up for the recognized disadvantages inherent in the combustion micromethod. In the hands of an experienced analyst, semimicroprocedures are as accurate and reliable, usually more so, as micromethods, and for less-experienced analysts the results in terms of effort and practice needed to obtain accurate analyses are far better. Unfortunately, the good features of combustion semimicroprocedures are generally established at the expense of a considerable increase in the sample size and in the time required for a single analysis. The sample size may be increased to as much as 20 to 30 mg., and the time needed for the combustion may be twice that required for a microsample.The semimicroproeedure described here was evolved to meet several qualifications: It was necessary to analyze samples as small as 12 to 13 mg., and a general level of 15 mg. for the sample was desired; it was necessary to have a high degree of accuracy and reliability in routine work; and it was desired to work as rapidly as in the micromethod. Furthermore, circumstances made it necessary' to work under ordinary laboratory' conditions with forced or window ventilation, under all conditions of temperature and humidity' throughout the year. The chief guide was provided by the work of Belcher (1, 2) who demonstrated that it was possible to employ' a flow rate of 50 ml. per minute of oxygen in both micro and macro combustion procedures, with a con-

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confidence: 77%

mentioning

confidence: 99%

Semimicrodetermination of Carbon and Hydrogen

Horning¹,

Horning²

1947

Anal. Chem.

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“…Although many prefer to keep the temperature at 650°to 750°C. (40,55,83,96,219), there is a trend toward increasing it, even as high as 10000 C. (8,232). The need for a preheater or preburner is also doubtful.…”

Section: Elemental Analysis Carbon and Hydrogenmentioning

confidence: 99%

“…Today they have been fairly well accepted. Clark and Stillson (40) and Horeischy and Bühler (95) have described semi-and fully automatic combustion apparatus, adding to the already extensive literature (40,219). The rate at which the burning or vaporizing furnace should move has not yet been settled, and consequently the only commercially available automatic device is provided with a variable-speed control.…”

Section: Elemental Analysis Carbon and Hydrogenmentioning

confidence: 99%

Organic Microchemistry

Willits¹

1949

Anal. Chem.

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MICROCHEMICALanalyses of organic compounds still follow largely the pattern set by Fritz Pregl. Considerable strides have been made during the past 6 years, as evidenced by the increase in the number of microchemical laboratories and the wider application of microanalytical chemical techniques. During the late twenties and early thirties, microanalytical methods were but little used in the United States except in the Atlantic Coast states. Ten years later these methods had been introduced into the midwestern states, and today micromethods are in use in analytical laboratories throughout the country.The keen interest shown in the development of microchemical analysis is exhibited by the establishment of a committee on the performance of microchemical balances (A. H. Corwin of Johns Hopkins University, chairman); a revival of the committee on standardization of microchemical apparatus (A. Steyermark, chairman); and the re-establishment of a referee on the standardization of microchemical methods by the Association of Official Agricultural Chemists. The British Standards Institute has formed a subcommittee to standardize microchemical apparatus, and the work of this subcommittee is well advanced. Microchemistry has gone a long way since Pregl devised this scheme of analysis, for it is no longer limited to the analysis of material available in only small amounts. Instead, it has an accepted place, along with micromethods, for the analysis of materials available in large amounts. The micromethod is superior, in that it is faster, more economical of reagents, and in many instances more precise and accurate.

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“…Speed was obtained mainly by the simultaneous combustion of two samples. Hallett (6), Royer, Norton, and Sundberg ( 14), and Steyermark (15) have reported successful use of motors to drive movable burners slowly and automatically over samples.…”

Section: Inmentioning

confidence: 99%

Determination of Carbon and Hydrogen by Combustion

Lescher¹

1949

Anal. Chem.

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Microdetermination of Carbon and Hydrogen. Modern Industrial Setup

Cited by 22 publications

References 7 publications

Semimicrodetermination of Carbon and Hydrogen

Semimicrodetermination of Carbon and Hydrogen

Organic Microchemistry

Determination of Carbon and Hydrogen by Combustion

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