Experimental studies for the detection of protein in trace amounts

Organic cyanine dye for detection of protein in trace amounts - dye reaction mechanism, methods of eliminating inorganic compound reaction with dye, and detection of humic aci

Method and apparatus for background signal reduction in opto-acoustic absorption measurement

The sensitivity of an opto-acoustic absorption detector is increased to make it possible to measure trace amounts of constituent gases. A second beam radiation path is created through the sample cell identical to a first path except as to length, alternating the beam through the two paths and minimizing the detected pressure difference for the two paths while the beam wavelength is tuned away from the absorption lines of the sample. Then with the beam wavelength tuned to the absorption line of any constituent of interest, the pressure difference is a measure of trace amounts of the constituent. The same improved detector may also be used for measuring the absorption coefficient of known concentrations of absorbing gases

Thermoluminescent aerosol analysis

A method for detecting and measuring trace amounts of aerosols when reacted with ozone in a gaseous environment was examined. A sample aerosol was exposed to a fixed ozone concentration for a fixed period of time, and a fluorescer was added to the exposed sample. The sample was heated in a 30 C/minute linear temperature profile to 200 C. The trace peak was measured and recorded as a function of the test aerosol and the recorded thermoluminescence trace peak of the fluorescer is specific to the aerosol being tested

Trace levels of metallic corrosion in water determined by emission spectrography

Emission spectrographic method determines trace amounts of inorganic impurities in potable water. The capability of this innovation should arouse considerable interest among plant biologists, chemists working in organic synthesis, and pathologists

Trace analysis of phosphates in small aqueous volumes

The indirect determination of trace amounts of phosphate through estimation of the molybdenum in the phosphomolybdic acid complex has been improved. The lower limit of spectrophotometric determination is about 0.10 μg

Kinetic-spectrophotometric method for the determination of trace amounts of bromide in seawater

A novel simple, sensitive and rapid kinetic-spectrophotornetric method is proposed for the determination of trace amounts of bromide. The method is based on its catalytic effect on the oxidation of methylene blue (MB) by hydrogen peroxide in strongly acidic solution. The oxidation reaction is activated by large amounts of chloride and can be monitored spectrophotometrically by measuring the decrease in the absorbance of MB at 746 run. The determination of bromide is performed by a fixed-time method at the first 100 s from the initiation of the reaction. Unlike other kinetic-spectrophotornetric methods for the determination of bromide, the proposed method does not require heating the solution. Bromide can be determined in the range from 80 to 960 mu g l(-1) with the detection limit of 35 mu g l(-1). The relative standard deviation of ten replicate determination of 480 mu g l(-1) bromide was 1.4%. The influence of potential interfering ions was studied. The proposed method was satisfactorily applied to the determination of bromide in seawater without interfering effect from chloride ion.</p

Studies in coprecipitation of trace amounts of elements

A new approach to preconcentration of trace amounts of elements has been demonstrated whereby traces of metals tied up as chelates are coprecipitated on a column of solid organic material. Complete coprecipitation was found to occur within very narrow pH ranges, thereby allowing separation as well as concentration of the elements by careful adjustment of acidity and concentration of chelating agent. The separation is based on the difference in stability constants of the metal chelates. Preliminary studies with different physical forms of the carrier precipitate, indicate adsorptive processes could play a significant role in the mechanism of the column-coprecipitation process. The applicability of Atomic Absorption Spectrophotometry for the determination of traces of metals in coprecipitation studies has been investigated. Sensitivity limits for nine elements have been established and the effect of certain organic reagents on their standard curves determined. A new quantitative indirect method for the determination of trace amounts of chelating agent has been described --Abstract, page [ii]

The temperature dependence of the reactions of HO2 with NO and NO2

Mixtures of N2O, H2, O2 and trace amounts of NO and NO2 were photolyzed at 213.9 nm at 245-328 K and about 1 atm total pressure (mostly H2). HO2 radicals are produced from the photolysis, and their reactions are reported

Detection of Trace Amounts of Toxic Metals in Environmental Samples by Laser-excited Atomic Fluorescence Spectrometry

Results for the direct determination of trace amounts of Pb and Cd in Antarctic and Greenland ancient ice and recent snow by laser-excited atomic fluorescence spectrometry (LEAFS) are presented. The whole procedure starting from field sampling, mechanical decontamination of the samples in an ultra-clean laboratory and final analysis of the decontaminated samples is described. The measured concentrations varied in the ranges 0.1–3 pg ml^(–1) for Cd and 0.3–30 pg ml^(–1) for Pb. The results for direct analysis by LEAFS agree favourable with those obtained by isotope dilution mass spectrometry and electrothermal atomic absorption spectrometry, which require time-consuming pre-treatment and pre-concentration stages