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Showing papers on "Detection limit published in 1974"



Journal ArticleDOI
TL;DR: The detector shows good linearity in the region 10–230 ppb of phenol, and combined with suitable concentration techniques, the lower limit of detection of phenols in environmental samples was shown to be about 0.4 ppb.

47 citations


Journal ArticleDOI
TL;DR: In this article, the use of controlledpotential electrolysis as a separation and preconcentration technique for metal wire flameless atomic absorption analysis has been studied and a detailed study of the effect of various experimental parameters on the determination of cadmium is presented.

45 citations


Journal ArticleDOI
S. Neumann1, M. Kriese1
TL;DR: In this article, the frequency-doubled radiation of flashlamp-pumped dye laser has been compared with the radiation of an eleotrodeless discharge lamp (EDL) and a hollow cathode lamp (HCL) as excitation light sources in non-flame atomic fluorescence spectrometric (AFS) measurements.

29 citations


Journal ArticleDOI
W. Pilz1, I. Johann1
TL;DR: In this article, a modification of this method is described, and the detection limit, defined as threefold standard deviation of the blank, was found to be 0.034 mc mole H2O2; this corresponds to less than 0,01 ppm H 2O2.
Abstract: There is an urgent need for a more sensitive method to determine small amounts of hydrogen peroxide in air. All known methods were examined in this laboratory. The approach, using photometric determination of hydrogen peroxide with titanium tetrachloride, which has earlier been used by the authors in biological materials for the determination of katalase, seemed to be most promising. In this paper a modification of this method is described. The detection limit, defined as threefold standard deviation of the blank, was found to be 0.034 mc mole H2O2; this corresponds to less than 0,01 ppm H2O2. A detailed description and discussion of the method is given, including statistical data.

27 citations


Journal ArticleDOI
TL;DR: A rapid, sensitive method is described for the quantitative determination of carbamazepine in plasma and the derivatives formed by the reaction of the drug and internal standard with dimethylformamide dimethyl acetal are stable for at least 17 h.
Abstract: A rapid, sensitive method is described for the quantitative determination of carbamazepine in plasma. The coefficient of variation of replicate extractions is typically within 5%. This procedure can be completed in 45 min and the derivatives formed by the reaction of the drug and internal standard with dimethylformamide dimethyl acetal are stable for at least 17 h. The lower limit of detection is 0.2 µg/ml of plasma.

24 citations


Journal ArticleDOI
TL;DR: In this paper, the results are printed out as concentration units directly from an automated continuous flow system with on-line minicomputer and printer, and the optimum sampling rate is 20 samples or 60 determinations per hour.
Abstract: Sodium, potassium and ammonium ions, in concentration ranges of natural and waste water samples, have been simultaneously determined by direct potentiometry, using sodium, potassium, and ammonia ion-sensitive electrodes. The results are printed out as concentration units directly from an automated continuous -flow system with on-line minicomputer and printer. The optimum sampling rate is 20 samples or 60 determinations per hour. Various water samples have been analyzed and the results compared to those obtained by the standard methods. The lower detection limits were 0.1 ppm for Na+ and NH4 + and 1.0 ppm for K+. The values of standard deviation were < 10%, with the exception of the lowest concentrations. The relative error was in the range of ± 2%. The correlation of standard and proposed methods was very good.

21 citations


Journal ArticleDOI
TL;DR: Helium-3 activation analysis has been applied to develop a very sensitive means of trace lead analysis and the excitation function for the production of 207Po from the reaction of 3He with lead of natural isotopic composition is presented.
Abstract: Helium-3 activation analysis has been applied to develop a very sensitive means of trace lead analysis. The procedure involves the bombardrment of samples with 3He particles to induce a Pb + 3He yields 207Po reaction on lead isotopes. The 992keV gamma -ray of 5.84-hr 207Po is used as the signal'' for lead determination. Only milligram amounts of srmpls are required, The excitation function for the production of 207Po from the reaction of 3He with lead of natural isotopic composition is presented. If necessary, destructive analysis may be carried out, and a radiochemical separation procedure to plate polonium onto a silver foil is discussed. The accuracy of the measurement is about 3 to 5% for comparative analyses. For absolute determinations, the error is estimated to be 9-12%. Under reasonable irradiation and counting conditions, the detection limit is approximately 50 pg/ cm2, corresponding to 0.5 ppb in a matrix 100 mg/cm2 thick.

19 citations


Journal ArticleDOI
TL;DR: A relatively simple high-performance liquid chromatographic method for the anlysis of p -aminobenzoic acid and some of its metabolites is reported, suitable for routine clinical determinations.

18 citations


Journal ArticleDOI
TL;DR: A sensitive flame-ionization GLC method is described for the determination of the new anticonvulsant, 1-(2,6-dimethylphenoxy)-2-aminopropane, in plasma and is compared with a simultaneously developed electron-capture technique, which was found to give no advantage applicable to the analysis.

14 citations


Journal ArticleDOI
01 Jul 1974-Steroids
TL;DR: The sensitivity of the radioimmunoassay of steroids is considerably reduced by high blank values which may be derived in part from co-chromatographed standards which are transported by the solvent.

Journal ArticleDOI
01 Jun 1974-Talanta
TL;DR: The proposed technique is accurate, rapid, and has a standard deviation of +/- 0.025 ppm at the 1 ppm level and is also applicable to a number of elements in aluminium- and iron-base alloys.

Journal ArticleDOI
TL;DR: In this article, a Varian carbon rod flameless atomizer was used to estimate trace amounts of selenium in biological samples by atomic absorption utilizing the Varian Carbon Rod Flameless Atomizer.
Abstract: Trace amounts of selenium in biological samples were estimated by atomic absorption utilizing a Varian carbon rod flameless atomizer. Samples were digested with nitric perchloric acids, selenium was separated from the interfering sample matrices by reduction-precipitation with ascorbic acid, redissolved in acid and five microliter aliquots were taken for analysis. For a variety of samples, the results were comparable with, but somewhat lower than, levels determined by fluoro-metry. Sensitivity and detection limit are 80 ng/ml and 60 ng/ml respectively; absolute sensitivity and detection limit are 4×10 −10 g and 3×10 −10 g respectively.

Journal ArticleDOI
TL;DR: Calibrations were performed with standard bromide solutions (NaBr suprapur, E. Merck, Darmstadt) in dist. water before and after each series of the photometrical gold chloride method (10), which is fairly specific for bromides and does not measure bromoureides.
Abstract: were measured at room temperature in plastic beakers. The minimum amount of fluid required was 0.5 mL Calibrations were performed with standard bromide solutions (NaBr suprapur, E. Merck, Darmstadt) in dist. water before and after each series of the photometrical gold chloride method (10), which is fairly specific for bromide and does not measure bromoureides. Normal values were obtained from patients or volunteers without a history of bromide or bromoureide intake during the previous 2 months. They had bromide serum levels below the detection limit of the photometric method (0.5 mmoles/1). The values given are means and standard deviation (S.D.).

Journal ArticleDOI
TL;DR: Testosterone, progesterone and androstenedione can be estimated simultaneously in a single ether extract of plasma, using the gas chromatography-mass spectrometer combination with single ion monitoring with good correlation with the radioimmunoassay results.

Journal ArticleDOI
TL;DR: In this paper, the interference effects of 27 elements, 6 acids and 4 organic liquids on the atomic fluorescence determination of tin with argon-hydrogen, argonoxygen-hydgen and argon separated air-acetylene flames were reported.

Journal ArticleDOI
01 Jan 1974-Analyst
TL;DR: A method for residue analysis, based on electron-capture gas chromatography following clean-up on a sulphuric acid-Celite column, is presented, and results for the herbicide are included.
Abstract: A method for residue analysis, based on electron-capture gas chromatography following clean-up on a sulphuric acid-Celite column, is presented. The limit of detection is 10 ng g–1. Recoveries have been investigated for different kinds of vegetables. The extraction efficiency of acetonitrile versus dichloromethane was checked in a separate experiment. Spectroscopic data and results for the herbicide are included.

Journal ArticleDOI
TL;DR: In this article, a simple non-dispersive atomic fluorescence spectrometer was used for the determination of zinc in aqueous solution with an argon separated air-acetylene flame; a detection limit of 0.001 p.p.m.

Journal ArticleDOI
TL;DR: In this paper, a fluorimetric method for the determination of citrate is described, which does not suffer from the normal interferences and achieves a fluorescence maximum at 430 nm when an excitation source of 340 nm is used.

Journal ArticleDOI
R.J. Hurtubise1
TL;DR: An atomic absorption method was developed for determining silicon in streptomycin without prior separation and a deuterium arc background corrector indicated a moderately high bias in the results.

Journal ArticleDOI
TL;DR: In this paper, a carrier distillation method for determination of boron in calcium fluoride is described, where the sample is mixed with 5 % copperoxyfluoride containing 200 ppm of gallium and the resulting spectra are recorded in the region 2200 to 2850 A employing Hilger large quartz spectrograph.
Abstract: A carrier distillation method is described for determination of boron in calcium fluoride. The sample is mixed with 5 % copperoxyfluoride containing 200 ppm of gallium. 50 mg of this mixture is loaded in pre-arced U. C. C. 1990 electrode and excited using 15 amp. d. c. arc. The resulting spectra are recorded in the region 2200 to 2850 A employing Hilger large quartz spectrograph. The detection limit for boron is 0.1 ppm and the precision of the method is ± 12%.

Journal ArticleDOI
01 Feb 1974-Talanta
TL;DR: The improved flourometric procedure with a detection limit of 0.001 ppm, increased precision and reduced interferences over the existing Al-PAN method is described, which is satisfactory for the determination of aluminium in bronze when an ion-exchange separation is used, but is not suitable for the determined aluminium in plants.

Journal ArticleDOI
TL;DR: In this paper, the authors used carbon adsorption and solvent extraction to extract the rhenium from the sample by using a spectrophotometric method, which achieved a detection limit of less than 1 p.p.b.