Rapid Semi-micro Method Research Articles

Rapid semi-micro method for separating non-ortho chlorinated chlorobiphenyls from other chlorobiphenyls

A method for separating common non-ortho chlorinated chlorobiphenyls, namely 3,4,4′-tri-, 3,4,4′,5-, 3,3′,4,4′-tetra, 3,3′,4,4′,5-penta-, and 3,3′4,4′,5,5′-hexachlorobiphenyl (IUPAC Nos. 37, 81, 77, 126, and 169) from other chlorobiphenyls in shellfish tissue at pg g–1 wet mass concentrations is described. The method is based on saponification followed by extraction into 2,2,4-trimethylpentane, clean-up by gel-permeation chromatography and sulfuric acid treatment, separation of non-ortho chlorinated chlorobiphenyls from other chlorobiphenyls using a Florisil–carbon column and measurement using capillary GC–low resolution MS with selected ion monitoring to eliminate many interfering materials. Recoveries of chlorobiphenyls (20–5000 pg g–1 wet mass) averaged 84.5 ± 6.5%. The detection limits (3 times the noise level) are 20 pg g–1 wet mass for IUPAC Nos. 37, 77, 81, and 126 and 50 pg g–1 wet mass IUPAC No. 169. The method gave results for non-ortho chlorinated chlorobiphenyl concentrations in lobster digestive gland tissues and Aroclors equivalent to those obtained by a conventional procedure.

A rapid semi-micro method for the separation of lipoprotein fractions that uses a benchtop ultracentrifuge

A rapid semi-micro method for the separation of lipoprotein fractions that uses a benchtop ultracentrifuge

Rapid Semimicro Method for the Determination of Methyl Mercury in Fish Tissue

Abstract A fast semimicro method for the determination of methyl mercury in fish tissue is described. The procedure involves extracting the methyl mercury into toluene as methyl mercuric bromide, partitioning the bromide into aqueous ethanol as a thiosulfate complex, and re-extracting into benzene as methyl mercuric iodide. Methyl mercury is quantitated with gas chromatography. The method is sensitive to 0.01 ppm. Recoveries of added methyl mercury were 99% and the presence of methyl mercury in the final extract was shown by thin layer chromatography and gas chromatography of the thin layer spot. A variety of mercurial compounds do not interfere in the analyses. The amounts of both methyl and total mercury found in a variety of tissues of aquatic animals are compared. The presence of a demethylase in seal is suggested by the findings of high levels of nonmethyl mercury. Additional cleanup by column chromatography on Florisil was necessary with certain samples. The gas chromatographic columns were kept operational by the intermittent injection of 3M potassium iodide. Due to column bleed and resulting detector contamination, the use of the easily cleaned concentric tube electron capture detector is recommended.

I. DETERMINATION OF BARLEY AND MALT NITROGEN CONTENT USING AN AUTOANALYSER TECHNIQUE

A rapid semi-micro method of Kjeldahl digestion and the use of an Autoanalyser for the estimation of digest ammonia content are described. Adoption of these methods has achieved throughput rates of 40 to 50 samples per hr. with resultant savings in labour and materials.

A rapid semimicro method for production of yeast mitochondria

A simple, rapid, cconomical method for the production of yeast mitochondria is deseribed in detail. Highly intact mitochondria are isolated from cells mechanically ruptured with a small colloid mill. Yields of about 10 mg mitochondrial protein per 30 gm cells routinely are obtained. Because enzymic pretreatment of cells is unnecessary, intact mitochondria can be prepared from both parent and mutant cell strains in various physiological states using a standard set of conditions.

A Rapid Semimicromethod for the Determination of Phosphorus and Barium in Biologic Preparations

Abstract The determination of phosphorus and barium is made on acid digests of tissues by a rapid gravimetric procedure. The precipitations of barium as the sulfate and phosphorus as ammonium phosphomolybdate are utilized. Complete precipitation of these compounds is achieved by use of a filter-aid.

The Causes of Natural Durability in Timber. Pt. VI. Measurement of Anti-termitic Properties of Anthraquinones fromTectona grandisL. f. by a Rapid Semi-micromethod

The Causes of Natural Durability in Timber. Pt. VI. Measurement of Anti-termitic Properties of Anthraquinones from<i>Tectona grandis</i>L. f. by a Rapid Semi-micromethod

Determination of carbon and hydrogen in organic compounds containing phosphorus and sulfur: A rapid semimicro method using silver permanganate

A rapid and an economical semimicro method for the determination of carbon and hydrogen in the organophosphorus and sulfur compounds is described. A short combustion tube filled with thermally decomposed silver permanganate is used for the oxidation of organic matter. The filling of the combustion tube combines with phosphorus, sulfur, and halides, retaining them inside the tube. Carbon dioxide and water are absorbed conventionally in Ascarite and Anhydrone absorption tubes. One carbon-hydrogen determination by this method takes 40 minutes.

A rapid routine method for the estimation of nicotine in tobacco.

THE nicotine content of tobacco varies between wide limits, depending on the species studied. With the view of estimating the nicotine content in tobacco species grown in India, particularly in those of low nicotine content obtained in grafting experiments, a rapid semi-micro method of distillation followed by a spectrophotometric method of estimation have been developed.

A rapid semimicro method for the determination of C14.

Abstract A rapid semimicro method is described for the determination of C 14 in small samples of organic material. At least four samples per hour may be oxidized easily and the resultant C 14 O 2 trapped as BaCO 3 and prepared for counting. Samples as small as 0.2 mg. of carbon may be analyzed within the limits of counting error and weighing error of the barium carbonate samples.

Quantitative Determination of Cellulose in Raw Cotton Fiber. Simple and Rapid Semimicro Method

Quantitative Determination of Cellulose in Raw Cotton Fiber. Simple and Rapid Semimicro Method