Showing papers on "Detection limit published in 1980"
TL;DR: The developed method of ion-pair reverse-phase high-pressure liquid chromatography enables one to separate adenine nucleotides in cardiac tissue extract within 10 min with recovery of about 98% and lowest detection limit of 10 −6 m.
158 citations
TL;DR: In this paper, 9-Diazomethylanthracene reacts with carboxyl groups to give an ester derivative which can be used as either a fluorescence or ultraviolet label for fatty acid analysis by high-pressure liquid chromatography.
131 citations
TL;DR: A micropolarimeter based on laser optics is interfaced to HPLC for application in trace organic analysis and it is possible to obtain extinction ratios four orders of magnitude better than that in standard instruments.
Abstract: A micropolarimeter based on laser optics is interfaced to HPLC for application in trace organic analysis. With the use of selected Glan prisms, selected cell-window material, and air-based Faraday rotators, it is possible to obtain extinction ratios four orders of magnitude better than that in standard instruments. A detection limit of 0.5 ..mu..g is demonstrated in the separation of sugars in a 200-..mu..L detection volume. Applications to the HPLC of untreated human urine are also presented. 4 figures.
106 citations
TL;DR: In this article, a new liquid chromatographic method with increased sensitivity was developed for the determination of isocyanates common in industrial environments, which was applied to toluene 2, 4- and 2, 6-diisocyanate (2, 4 and 2 6-TDI).
Abstract: A new liquid chromatographic method with increased sensitivity has been developed for the determination of isocyanates common in industrial environments The isocyanates are converted to stable urea derivatives by reaction with 9-(N-methylaminomethyl)-anthracene These derivatives were analyzed using high performance liquid chromatography on a bonded octadecylsilyl phase using isocratic elution with acetonitrile/water and detected either by a UV or a fluorescence detector The method was applied to toluene 2, 4- and 2, 6-diisocyanate (2, 4- and 2, 6-TDI), hexamethylene diisocyanate (HDI) and 4, 4-diphenylmethane diisocyanate (MDI) The influence of various salts on the retention of the reagent amine was studied, as well as the separation of the urea derivatives on different C18-phases The detection limit is about 1 · 10−4 mg/m3 for the isocyanates investigated, using either UV or fluorescence detection This means that the new method is ten to twenty times more sensitive than the previously desc
72 citations
TL;DR: In this paper, the main interaction between the stationary phase and the solute is hydrogen bonding, hydrophobicity of the packing being negligible, and a colorimetric detection of a reduced form of Tetrazolium Blue served for the determination (limit of detection: 10 ng of saccharide).
64 citations
TL;DR: An improved method for determination of aluminum in serum by atomic absorption spectrophotometry with a graphite furnace with the detection limit is 2 microgram/L.
Abstract: We describe an improved method for determination of aluminum in serum by atomic absorption spectrophotometry with a graphite furnace. Interferences have been controlled and total combustion of the samples achieved by the use of new diluent in a molybdenum-treated graphite tube. The detection limit of this method is 2 microgram/L.
64 citations
TL;DR: In this paper, a detailed characterization of liquid phase flow-through detection systems as used in column liquid chromatography and flow injection analysis is discussed, including linear range, selectivity, peak broadening and detection limit.
59 citations
TL;DR: An arsine evolution-electrothermal atomic absorption method is described for the determination of ng/mL concentrations of total arsenic in urine and water and accuracy was established with two different National Bureau of Standards Standard Reference materials.
Abstract: An arsine evolution-electrothermal atomic absorption method is described for the determination of ng/mL concentrations of total arsenic in urine and water. Organic-arsenic compounds are decomposed with nitric, sulfuric, and perchloric acids. Sodium borohydride, a redesigned hydride generator, and an electric-heated absorption tube are used for arsine evolution and its conversion to atomic arsenic. The method has a detection limit of 6 ng/mL, a sensitivity of 1 ng/mL, and is linear from 0 to 110 ng/mL of arsenic. Accuracy was established with two different National Bureau of Standards Standard Reference materials, and mean errors from 0 to -2 were obtained.
58 citations
TL;DR: In this paper, the relative and absolute Raman scattering intensities or aqueous thiosulfate were used for in situ determinations of species in equilibria and reactive mixtures.
56 citations
TL;DR: In this article, an investigation of a commercially available three electrode d.c. plasma source burning in an inverted Y configuration was carried out and it was shown that for atoms the position of maximum line intensity in the plasma is determined by the norm temperature of the spectral line.
53 citations
TL;DR: In this article, the determination of nitrate and bromide directly from aqueous extracts by high-performance liquid chromatography on an amino phase chemically bonded to silica gel is described.
TL;DR: In this article, an instrumentation and analytical procedures for the direct determination of lead, copper and cadmium in alcoholic beverages in the concentration range 1-100 μg 1-1 are outlined.
TL;DR: An automated procedure for the determination of soluble arsenic, using hydride generation atomic absorption spectroscopy, is described and optimised operating conditions are derived in this article, where the detection limit (based on twice the standard deviation for 15 blank measurements) is 0.90 ng ml-1 of arsenic for arsenic(III), arsenic(V) and methylarsenic species.
Abstract: An automated procedure for the determination of soluble arsenic, using hydride generation atomic-absorption spectroscopy, is described and optimised operating conditions are derived. Interferences are observed in the presence of silver(I), gold(III), iron(III), platinum(IV), antimony(III), strontium(II), fluoride and sulphide but can be overcome by suitable pretreatment procedures. The detection limit (based on twice the standard deviation for 15 blank measurements) is 0.90 ng ml–1 of arsenic for arsenic(III), arsenic(V) and methylarsenic species. A 10% negative bias of results is observed in the determination of dimethylarsenic species.
TL;DR: In this paper, a heat-induced refractive index change was used to increase the sensitivity of the spectrophotometric determination of iron(II) in a dual-beam system.
TL;DR: In this paper, a high-performance liquid chromatographic procedure is described for the quantitative determination of epinephrine, norepinephrine, and dopamine in human plasma, which is based on adsorption of the catecholamines to alumina and, after liberation, separation on a microparticulate bonded strong cation exchange resin and amperometric detection, has been optimized to give complete baseline separation of the substances of interest.
TL;DR: In this paper, a method for direct determination of cadmium in undiluted sea water by graphite-furnace atomic absorption spectrometry is described. But this method requires very careful temperature control and accurate background compensation.
TL;DR: A high-performance liquid chromatographic system was developed with baseline separation of coenzyme A (CoASH) from dephospho-coen enzyme A and acetyl-coanzyme A using isocratic elution and could be used without modification for the estimation of the content of CoASH in biological extracts, e.g. mitochondria.
TL;DR: A high pressure liquid chromatography procedure was developed for analysis of cocaine and two metabolites (norcocaine and benzoylecgonine) in biological fluid and confirmation of the individual compounds was made by direct probe mass spectral analysis of the eluted peaks and comparison to known standards.
Abstract: A high pressure liquid chromatography procedure was developed for analysis of cocaine and two metabolites (norcocaine and benzoylecgonine) in biological fluid. Following extraction with chloroform/Isopropanol (3/2), chromatography is performed with a mu-Bondapak C-18 reverse phase column eluted with water/acetonitrile/methanol (8/1/1) containing 1% acetic acid and 0.3 M EDTA. Ultraviolet detection of individual compounds was made at 235 nm and quantitation was based on peak height ratio to internal standard. Detection limit based on 0.5 mL of sample is less than 1 microgram/mL. Confirmation of the individual compounds was made by direct probe mass spectral analysis of the eluted peaks and comparison to known standards.
TL;DR: The residues in meat of seven estrogenic drugs used in anabolic preparations for animal production were analysed as trimethylsilyl ethers by electron-impact gas chromatography-mass spectrometry following a simple clean-up procedure.
TL;DR: A gas-chromatographic procedure for the analysis of oxalic acid requires relatively small quantities of urine (1 ml) or plasma (5 ml) and the lower limit of detection is 20 nmol.
TL;DR: In this article, a differential pulse polarographic determination of molybdenum in nitrate media is described and the effects of pH, nitrate concentration, temperature, and cationic and anionic interferents on the peak current are reported.
TL;DR: Chromatographic conditions for the determination of 5-methyltetrahydrofolic acid in plasma and spinal fluid are described, involving simple pretreatment of the sample and Electrochemical detection was used.
TL;DR: In this paper, a method is presented for the simultaneous determination of a wide range of carboxylic acids and phenols in water using extractive alkylation with the tetrabutylammonium ion as counter ion and pentafluorobenzylbromide as alkylating agent.
Abstract: A method is presented for the simultaneous determination of a wide range of carboxylic acids and phenols in water. Extractive alkylation is used with the tetrabutylammonium ion as counter ion and pentafluorobenzylbromide as alkylating agent. Extracts are analyzed by glass capillary gas chromatography and electron capture detection. Using one ml of water sample, the detection limit lies in the range of 1–10 μg/l. Application has been made to the analysis of steam condensate and domestic sewage effluent.
TL;DR: Trace amounts of selenium(VI) and total seenium in human blood and plasma were determined with a practical detection limit of 2 ng.
Abstract: Selenium(IV) reacts with 1,2-diamino-3,5-dibromobenzene to form 4,6-dibromopiazselenol, which is detected by means of a gas chromatograph equipped with an electron-capture detector. Trace amounts of selenium(VI) and total selenium in human blood and plasma were determined with a practical detection limit of 2 ng.
TL;DR: In this paper, a pulsed laser is used as the excitation source to enhance the selectivity for polycyclic aromatic hydrocarbon mixtures by high-performance liquid chromatography.
TL;DR: In this article, a high-performance liquid chromatographic (HPLC) method was used to analyze a mixture of plant hormones, including indole-3-acetic acid derivatives.
TL;DR: Sulphide (0.1 ng/ml) is determined by measuring the chemiluminescence given by its oxidation in aqueous solution by hydrogen peroxide, catalysed by peroxidase.
TL;DR: The zone immunoelectrophoresis method shows the following advantages: less consumption of antibodies; much lower detection limit (0.05 microgram of protein per ml); larger concentration range with a linear calibration curve.
Abstract: Quantitative determination of proteins has been made by electrophoresis thereof in tubular canals filled with agarose gel containing antibodies. The procedure is simple and practicable. Sample volumes of a few microliter up to some hundred microliter may be added for each test. The amount of protein in a sample was found to be linearly related to the distance from the point of application (i.e. gel surface) to the front of the immunoprecipitation zone. The zone immunoelectrophoresis method shows over rocket immunoelectrophoresis the following advantages: less consumption of antibodies; much lower detection limit (0.05 microgram of protein per ml); larger concentration range with a linear calibration curve. A high correlation (0.98) between the first- and last-mentioned method was obtained for alpha 1-antitrypsin. Precision data are given for albumin and alpha-fetoprotein and typically a relative standard deviation of a few percent was obtained.