Showing papers on "Detection limit published in 1969"
TL;DR: In this article, confidence limits for the precision parameter k used in the analysis of palaeomagnetic data and for the angular standard deviation σ were calculated for 95 per cent and 99 per cent confidence limits.
Abstract: Summary
Confidence limits are calculated for the precision parameter k used in the analysis of palaeomagnetic data and for the angular standard deviation σ.
A set of tables for 95 per cent and 99 per cent confidence limits is presented.
286 citations
01 Nov 1969
TL;DR: Anions adsorption at platinum determined by ellipsometry, finding perchlorate and fluoride ions adorption below detection limit as discussed by the authors, using ellipsometrical ellipsology.
Abstract: Anions adsorption at platinum determined by ellipsometry, finding perchlorate and fluoride ions adsorption below detection limit
61 citations
TL;DR: Following wet ashing with chloric reagent, the iodine-catalyzed cerate-arsenite reaction was carried out at temperatures between 23 and 27°, and the reaction rate coefficients were corrected to refer to 25.0° by an empirical equation.
Abstract: A method for the measurement of subnanogram quantities of iodine is described. Procedural detail and precision of results are presented for application of the method to protein-bound or total iodine in duplicate on 12.3 µl serum. Following wet ashing with chloric reagent, the iodine-catalyzed cerate-arsenite reaction was carried out at temperatures between 23 and 27°, and the reaction rate coefficients were corrected to refer to 25.0° by an empirical equation. The recovery of iodine standards, added to the precipitated protein before ashing, ranged between 96 and 106%. One contributing cause of this variation is the formation of an inhibitor of unknown nature during heating. Samples were brought to a final volume of 180 µl prior to fading. The detection limit was of the order of 0.04 ng iodine. For 62 serum samples having a mean iodine content of 0.558 ng (range 0.15-1.31 ng), the standard deviation calculated from duplicates was 0.019 ng/180 µl. For 31 samples having a mean iodine content of 2.24 ng (range 1.61-2.96 ng), the standard deviation was 0.039 ng/180 µl. Expressed as micrograms of iodine per 100 ml of serum, the mean ± standard deviation for the group of 62 samples was 4.54 ± 0.15.
17 citations
TL;DR: The increased sensitivity provided by the atomic absorption technique results in a 30-fold decrease in the amount of protein required for analysis by the usual spectrophotometric method.
17 citations
TL;DR: In this paper, an atomic fluorescence spectroscopic method was described for the assay of silicon in low alloy steels, with a detection limit of 0.7 ppm at 351.6 nm compared to 4 ppm for atomic absorption at the same wavelength.
Abstract: An atomic fluorescence spectroscopic method is described for the assay of silicon in low alloy steels. The method reported is more sensitive than the corresponding atomic absorption method, the detection limit being 0.7 ppm at 351.6 nm compared to 4 ppm for atomic absorption at the same wavelength.
6 citations
01 Jan 1969
4 citations
TL;DR: In this article, a neutron activation analysis for simultaneous determination of cobalt, iron, indium and cadmium in electrolytic zinc sulphate solutions is described, the chemical separation, in hydrochloric acid medium, involved anion exchange followed by solvent extraction.
4 citations
TL;DR: In this paper, the lower limit of detection of diethylamine or triethylamine vapors by drawing the vapor through a detector tube containing silica gel impregnated with dichloroacetaldehyde and then heating is 25 μg.
Abstract: Methods are described for the detection of amines as vapors and in solution. The lower limit of detection of diethylamine or triethylamine vapors by drawing the vapor through a detector tube containing silica gel impregnated with dichloroacetaldehyde and then heating is 25 μg. As low as 1 μg of the same amines can be detected In aqueous solution by the degradation of a chloral-dichloroacetaldehyde copolymer. Detection signal in the latter case is the appearance of fluorescence when liberated monomer dissolves a 2-diphenylacetyl-1,3-indandione derivative.
4 citations
TL;DR: In this paper, the lower limit of detection for a very low-level background (B < 4) has been studied and a graph is presented which allows to find quickly, for a given background, the critical value of the count difference and the lower-limit of detection.
4 citations
TL;DR: In this article, the optimum conditions for the determination of silicon by flame emission spectrometry were ascertained, where the maximum signal emanates from a region immediately above the tip of the inner cone of a fuel-rich oxygen-acetylene flame.
Abstract: Optimum conditions for the determination of silicon by flame emission spectrometry were ascertained. The maximum signal emanates from a region immediately above the tip of the inner cone of a fuel-rich oxygen-acetylene flame. The organosilicon compound is aspirated as a solution in ethanol and the emission intensity at 2516.1 A is measured. Quantitative determinations were made using a working curve and by the method of standard addition. Detection limit is 3.5 μg/ml.
1 citations
TL;DR: In this article, the sensitivity for silver in silica using radioisotopic X-ray sources, electronic discrimination with a single-channel analyzer, and scintillation detectors was determined as a function of excitation energy.