ABSTRACT
In order to investigate the mechanism of Gram staining of bacteria, tests with anionic dyes followed by treatment with cationic octyltrimethylammonium (OTMA) were carried out. The study revealed that tetrabromophenolphthalein ethylester (TBPE) gave the most reliable staining of Gram-negative bacteria with negative staining of Gram-positive bacteria. Tests on many species of bacteria showed that TBPE positive bacteria were Gram-negative and vice versa, without exception.
Subject(s)
Bacteria/classification , Gentian Violet , Phenazines , Staining and Labeling/methods , Ethanol , Quaternary Ammonium Compounds , SolubilityABSTRACT
The hydrophobicity of myelinic, synaptosomal and mitochondrial surfaces in the rat brain was measured using the nonionic surfactant, C18H37O(CH2CH2O)13H. This method is based on the adsorption of the hydrophobic alkyl group of the surfactant by the hydrophobic sites on the surfaces. Each preparations was mixed with an excess of the surfactant and the surfactant remaining in the supernatants was determined spectrophotometrically by measuring the absorbance of tetrabromophenolphthalein ethylester at 690 nm. The greatest amount was adsorbed by myelin, followed by synaptosomes and mitochondria. The hydrophobicity is shown to be a reflection of the surface lipids. This method showed good reproducibility and was useful for the quantitative determination of hydrophobicity.
Subject(s)
Brain/metabolism , Membrane Lipids/metabolism , Mitochondria/metabolism , Myelin Sheath/metabolism , Plant Oils , Polyethylene Glycols/pharmacokinetics , Synaptosomes/metabolism , Animals , RatsABSTRACT
4,6-Di-tert-butyl-3-methoxycatechol (DBMC) has been developed as a new reagent for boron, the complex anion formed being extracted as an ion-associate with Ethyl Violet into toluene, and the absorbance measured at 610 nm. The calibration graph is linear up to 0.43 mug of boron, the molar absorptivity is 1.02 x 10(5) 1.mole(-1).cm(-1) and the relative standard deviation 1.2%. The method has been applied to the determination of boron in sea-water and river water with satisfactory results.
ABSTRACT
Nitrite in river and sea-water was determined fluorometrically by flow-injection analysis. In acidic medium, nitrite was reacted with 3-aminonaphthalene-1,5-disulphonic acid (C-acid) to form the diazonium salt, which was converted into the fluorescent azoic acid salt in an alkaline medium. The carrier stream, into which the sample solution was injected, was distilled water. The reagent solution stream, which contained C-acid, EDTA and hydrochloric acid, was mixed with the carrier stream in a 13-m length of Teflon tubing (bore 0.5 mm) maintained at 90 degrees in a thermostatic bath. After passing through the mixing coil, the stream was mixed with an alkaline solution. The fluorescence intensity (excited at 365 nm) was measured at 470 nm. The detection limit (S N = 3) was 1 x 10(-9)M (14 ng 1 . nitrite-nitrogen) and the RSD of 10 injections of 10(-6)M nitrite was 0.4%. Analyses can be done at a rate of up to 45 hr .
ABSTRACT
Molybdophosphate, formed between orthophosphate and molybdate in sulphuric acid solution, is extracted into a mixture of toluene and 4-methylpentan-2-one (1:3 v v ) with Malachite Green as counter-ion. A single extraction with equal phase volumes gives an apparent molar absorptivity for phosphate of 2.3 x 10(5) l.mole(-1).cm(-1) at 630 nm; the absorbance of the reagent blank is 0.03. With an organic to aqueous phase-volume ratio of 1:10, the molar absorptivity is 2.5 x 10(5) l.mole(-1).cm(-1) and the absorbance of the reagent blank 0.08. By the proposed method, ng ml levels of phosphorus can be determined, and the detection limit is about 0.1 ng ml . The standard deviation and relative standard deviation for the determination of phosphorus in tap water (4.3 ng ml ) are 0.05 ng ml and 1.1%, respectively. The method can also be applied to the determination of phosphorus in river water and sea-water.
ABSTRACT
The importance of selecting the most suitable counter-cation in the solvent extraction-spectrophotometric determination of an anionic metal chelate containing a sulphonic acid group is demonstrated and discussed. In the case of cobalt and 2-nitroso-1-naphthol-4-sulphonic acid (nitroso-NW acid), the most suitable counter-cation is the tetrabutylammonium ion (Bu(4)N(+)): in this case only the ion-pair of the anionic cobalt chelate is extracted into chloroform and the excess of the nitroso-NW acid remains in the aqueous phase. The absorption maximum of the chelate in chloroform is at 307nm, at which the molar absorptivity is 6.5 x 10(4)l.mole(-1).cm(-1). The absorbance of the reagent blank at 307 nm is less than 0.010. By use of nitroso-NW acid and Bu(4)N(+), trace amounts of cobalt may be determined in nickel salts and in iron and steel samples.
ABSTRACT
The solvent extraction of non-ionic surfactants with potassium chloride and tetrabromophenolphthalein ethyl ester potassium salt has been studied, and a method developed for determining trace amounts of non-ionic surfactants in water spectrophotometrically. Various non-ionic surfactants of general type RO(CH(2)CH(2)O)(n)H (where R is an alkyl or alkylphenyl group and n is the number-average degree of polymerization) are extracted quantitatively into o-dichlorobenzene from the water sample, and reacted in the organic phase with tetrabromophenolphthalein ethyl ester potassium salt to give a coloured product, the absorbance of which is measured at 620 nm.
ABSTRACT
Formation of piazselenols by the reaction of Se(IV) with 1,2-diaminobenzene and its derivatives, followed by solvent extraction and gas chromatography with electron-capture detection, provides the most sensitive means of determining selenium. By suitable chemical manipulation, the method can be used for Se(-II), Se(O), Se(IV) and Se(VI). Applications to a wide variety of samples are reviewed.
Subject(s)
Selenium/blood , Adult , Aged , Chromatography, Gas/methods , Female , Humans , Infant, Newborn , Male , Middle AgedABSTRACT
The simple removal of excess of co-extracted reagent in the solvent extraction of anionic metal complexes with a quaternary ammonium salt greatly improves the determination of aluminium with Pyrocatechol Violet (PV) and zephiramine (tetradecyldimethylbenzylammonium chloride). The exchange equilibrium constants for PV reagent and aluminium complex with four univalent anions (halides and nitrate) were determined when chloroform and 1,2-dichloroethane were used as extracting solvents. The constants were compared with those obtained with Pyrogallol Red. The method with PV and chloroform is suitable for the determination of micro-amounts of aluminium in river water. The apparent molar absorptivity of the aluminium complex in chloroform is 8.9 x 10(4) 1 mol(-1) cm(-1) at 587 nm. The limit of detection and precision achieved with the method are 3 mug l(-1) and within 4% respectively. A large excess of reagent can be used, and the ternary complex can be completely extracted over the pH range 5.5-10. Masking agents allow most interferences to be suppressed.
ABSTRACT
The stability constants of the Mn(2+), Fe(2+), Co(2+), Ni(2+), Cu(2+) and Zn(2+) complexes with four acids of the type HOOCCH(2)O(CH(2)CH(2)O)(n) CH(2)COOH (n = 0-3) are reported. For n = 0 the constants are in the Irving-Williams order, but not for n = 1-3.
ABSTRACT
Iron has been determined in sea-water by extraction of the ternary complex of iron(II) with 2-nitroso-4-chlorophenol and Rhodamine B at pH 4.7 and measurement at 558 nm. Toluene is used as the organic solvent. Any iron(III) is reduced with hydroxylammonium chloride.
ABSTRACT
Ultramicro amounts of selenium in pure sulphuric acid are converted into selenous acid with a bromine-bromide redox buffer solution. The selenous acid reacts quantitatively with 4-nitro-o-phenyl-enediamine to form 5-nitropiaselenol which can be extracted into toluene. The extract is very sensitive to electron-capture detection in gas chromatography, and the sensitivity is higher than that of 5-chloro-or 4, 5-dichloro-piaselenol. The calibration curve (peak heights) is linear up to 0.15 mug of selenium in 1 ml of toluene. Pure sulphuric acid, commercially available, contains 10(-6)$ 10(-5) % selenium.
ABSTRACT
4-Chloro-o-phenylenediamine reacts with selenous acid at pH 0-1 to form 5-chloropiaselenol, which is then extracted into 1 ml of toluene. The toluene layer is injected into an electron-capture detector gas Chromatograph. From the peak height selenium is determined, the minimum amount detectable being about 0.04 mug.
ABSTRACT
A simple procedure for the successive chelatometric titration of calcium and magnesium in natural waters, with 3',3''-bis(2-hydroxy-3-carboxy-naphthaleneazo)phenolphthalein as indicator, is described.
ABSTRACT
Some new phthaleinazo compounds-o,o'-dihydroxyazo compounds-have been prepared by coupling chromotropic acid, R-acid, and 2-hydroxy-3-naphthoic acid with bis-diazotized diaminophthaleins. These compounds have been found to be very sensitive colour reagents for alkaline earths in alkaline media, and in particular, bis(chromotropeazo)phenolphthalein is the most sensitive yet found.
ABSTRACT
Few colour reagents are known for lithium. Of several hundreds of reagents synthesised by the authors and their collaborators, o,ot-dihydroxyazo compounds were found to be the best, especially those with beta-naphthol derivatives as a coupling component. The bluish colour of the reagent turns to red in the presence of lithium.
