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A Rapid Manometric Method for the Determination of Carbonate in Soils
Author(s) -
Williams D. E.
Publication year - 1949
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1949.036159950013000c0021x
Subject(s) - chemist , citation , soil water , carbonate , library science , computer science , chemistry , soil science , geology , organic chemistry
IT is often desirable to have a more rapid way of determining the carbonate content of soil than is afforded by the standard A. O. A. C. method. Where rapidity of measurement and convenience of procedure are preferred, the manometric method may be used with very little sacrifice of accuracy. Passon's method as modified by H. R. Skewes increased the rapidity of the determination by separating the manometer from the reaction vessel. The separation limits the number of determinations to the number of reaction vessels. This modified apparatus is inconvenient in that it requires special caps for connecting the manometer to the reaction vessels. Also there is the possibility that leaks may develop in the vessel due to loose or broken stopcocks or to a crack in the cemented seal. Skewes' apparatus is as follows: The reaction vessel "consists of an ordinary 6-ounce wide mouthed bottle taking a screw-on lid. The screw-on lid is made of tin plate, strengthened by a flat plate of metal on top, and protected from corrosion by a coating of colorless synthetic enamel. A stainless steel tube, one inch long, is soldered into the center of the lid, and a stopcock B, and bulb tube, 2 mm bore, is rigidly fixed into the stainless steel tube by means of de Khotinsky's cement. The bulb tube prevents spray from being carried over into the manometer. A soft rubber washer is used to make a gas-tight union between the lid and the bottle. For pressure measurements the completed assembly is connected to the manometer by a short length of rubber tubing.