Micro-Carius Halogen and Sulfur Determination

Abstract

Through suitable combination of a number of favorable factors it was possible to unify, standardize, and improve the prevalent micro-Carius methods for halogen and sulfur to such an extent that one apparatus and one method of digestion, as well as an identical filtration procedure, can now be applied to the determination of both types of elements. Some of the difficulties inherent in the micro-Carius method have been partially or totally remedied. THE micro-Carius determination of halogen and sulfur possesses numerous advantages, not only as a method to be taught to students, but also as a generally useful analytical procedure. Despite its simplicity, it is most reliable and can be applied to liquids and volatile substances as well as to solids. Furthermore, it offers a high degree of precision because it has no blank and because it involves simple stoichiometric reactions.Prevailing objections to the Carius determination are: the danger of explosions, the long heating period, and the possibility of contaminating the reaction product with glass splinters.An investigation is here described which was undertaken to minimize the above-mentioned difficulties and to unify as well as standardize the apparatus and the procedures. It was found that a combination of the early micro-Carius method of Emich (1) with the conventional micro-Carius method of Pregl (7) aids in overcoming the first two objections while application of the method of differential weighing of the silver halide precipitate in the case of halogen determination, and application of the benzidine method of Guillemet (3) and Weygand and Hennig (9) in the case of the sulfur determination, serve to eliminate the last objection.The apparatus and procedure employed in this work were those described by Niederl and Niederl (6), except where modifications are specifically mentioned. ApparatusBomb Furnace (6, p. 122). Any metal block or cylinder with suitable borings for the pressure tubes can be used. The heating may be done by gas or electrically (4).Pressure Tubes (6, p. 122). The pressure tubes are of straight-walled Pyrex glass without a constricted end. They are 20 cm. long, 9 to 10 mm. in inside diameter, and should have a

The measurement of radioactive sulphur (35S) in biological material

“…A study was made of the conditions which must be observed if this method is to be applied to biological material. After the material had been oxidized, the sulphate was precipitated as benzidine sulphate by a procedure based on that described by Niederl, Baum, McCoy & Kuck (1940) In order to do this it was necessary to know the approximate S content of the material being analyzed. There islittle information on the total S content of tissues to be found in the literature.…”

“…), and similar values for the tissues of other animal species have been reported (Silberstein, 1934;Brown & Klauder, 1935;Masters & McCance, 1939;Sherman, 1941 Experiments were conducted in which the size of the Carius bomb, the amount of HNO3, and the time and temperature of heating the bomb were varied until a satisfactory set of conditions was found for the oxidation of 0-3-0-5 g. of tissue. The methods used for the evaporation of the contents of the bomb and for the precipitation of the sulphate with benzidine hydrochloride were based on those used by Niederl et al (1940) for the microdetermination of S in organic compounds. Benzidine sulphate separates well when centrifuged, and when 3S was to be measured, the benzidine sulphate was separated and washed in a centrifuge tube before depositing it on a Petri dish for radioactivity measurements.…”

“…Benzidine sulphate separates well when centrifuged, and when 3S was to be measured, the benzidine sulphate was separated and washed in a centrifuge tube before depositing it on a Petri dish for radioactivity measurements. When the method was applied to the gravimetric determination ofS, the benzidine sulphate was collected on a microfilter with a fritted disk, washed, dried and weighed as described by Niederl et al (1940 The general procedure adopted for preparing and sealing the Carius bombs was that described by Niederl et al (1940).…”

Studies on the Digestion of Wool by Insects VIII. the Significance of Certain Excretory Products of the Clothes Moth, Tineola Bisselliella, and the Carpet Beetle, Att Agenus Piceus

“…pressure for 20 min. Total and soluble sulphur: Micro-Carius digestion followed by precipitation of benzidine sulphate (Niederl et al 1940). The precipitate was dissolved in hot N/50 NaOH and backtitrated with N/50 HCI, using neutral red as indicator.…”

The Mode of Action of Phenothiazine as an Anthelmintic. The Uptake of 35S-Labelled Phenothiazine by the Tissues of Nematode Parasites and Their Hosts

“…It was found that the sulphur in such amounts of tissue could be suitably oxidized by the micro-Carius method (Niederl et al 1940), 0.25 ml. of concentrated nitric acid and 5 mg. sodium bromide being used per sample.…”