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Model Based Determination of Detection Limits for Proton Transfer Reaction Mass Spectrometer

References Arendacká, B., Schwarz, K., Štolc, S., Wimmer, G., Witkovský, V. (2008). Variability issues in determining the concentration of isoprene in human breath by PTR-MS. Journal of Breath Research 2(3), 037007 (8pp). Arinbruster, D., Tillman, M., Hubbs, L. (1994). Limit of detection (LOD) / limit of quantitation (LOQ): Comparison of the empirical and the statistical methods exemplified with GC-MS assays of abused drugs. Clinical Chemistry 40(7), 1233-1238. Cox, C. (2005

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Comparison of Minimum Detectable Concentration with the IUPAC Detection Limit

methods including detection and quantification capabilities. IUPAC Recommendations 1995. Pure & Appl. Chem. 67, 1699-1723. Mocak, J., Bond, A. M., Mitchell, S., Schollary, G. (1997). A statistical overview of standard (IUPAC and ACS) and new procedures for determining the limits of detection and quantification: Application to voltammetric and stripping techniques. IUPAC Technical Report 1997. Pure & Appl. Chem. 69, 297-328. Mocak, J., Bobrowski, A. (2001). Determination of cadmium and lead in water - new

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POSSIBILITY OF THE SPECTROPHOTOMETRIC DETERMINATION OF EUROPIUM BY MEANS OF ARSENAZO III

Abstract

The concentration of Eu(III) cations in model aqueous solutions can be quantified by means of Arsenazo III reagent. Absorbance of the solution was measured at the wavelength λmax = 655 nm. Molar absorptivity reached the value ε655 = 5.5±0.2 · 104 cm-1 mol-1 · dm3. Beer's law was obeyed in the range from 0 to 2 mg · dm-3 Eu(III). The value of limit of detection was established by application of 3σ approach and reached the value of 20.9 μg · dm-3. Repeatability of analysis expressed by relative standard deviation does not exceed the value of ± 8% and apparent recovery lay in acceptable range from 91 to 106 %. Stoichiometry between Eu(III) and Arsenazo III in media of relevant solution was 1:1. The absorbance of the solutions within the linear range of the proposed method maintained a constant value for 60 minutes. Described procedure can be utilized to determination of Eu(III) concentration in real samples, but it is necessary eliminate interfering ions. Cations like La(III), Sm(III), Th(IV), U(VI) and complexing agent EDTA cause significant error at the determination of Eu(III) in model solution. Presented spectrophotometric method could be applied for the determination of europium in the minerals and water samples, however after a suitable separation and preconcentration of target analyte.

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Electrochemical and analytical performance of boron-doped diamond electrode for determination of ascorbic acid

Abstract

The electrochemical behavior and determination of ascorbic acid (AA) was investigated at a bare boron-doped diamond (BDD) electrode using cyclic and differential pulse voltammetry. The influence of pH of supporting electrolyte and scan rate on the current response of analyte was examined to select the suitable experimental conditions. It was found that AA provided one well-shaped irreversible and diffusioncontrolled oxidation peak at +0.87 V vs. Ag/AgCl in Britton-Robinson buffer pH 4.0. Applying differential pulse voltammetry, the peak current of AA was linearly proportional to its concentration from 5 × 10-6 to 2 × 10-4 mol L-1 (R2 = 0.999), with the limit of detection of 1.1 × 10-6 mol L-1 and the good repeatability (relative standard deviation of 2.3 %). The developed electroanalytical protocol was successfully applied to determine the content of AA in commercial pharmaceutical preparations, based on the standard additions method, with the obtained recovery of 122 %. The accomplished analytical performance indicates that BDD electrodes are promising electrochemical sensors for pharmaceutical analysis.

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Heavy metals determination using various in situ bismuth film modified carbon-based electrodes

Abstract

The proposed work deals with the utilization of three carbon-based electrode substrates such as boron-doped diamond, glassy carbon and carbon paste for the preparation of in situ bismuth film modified electrodes. Such modified electrodes were subsequently used for the differential pulse anodic stripping voltammetric determination of heavy metal cations (Zn2+, Cd2+ and Pb2+) individually and simultaneously using similar experimental conditions (0.1 mol l−1 acetic buffer solution of pH 4.5 as supporting electrolyte with the addition of 0.1 mmol l−1 Bi3+, deposition potential of −1.4 V and deposition time of 120 s). The results showed that the modification step mostly enhanced the deposition and stripping process of studied cations when compared to the bare electrode substrates. A boron-doped diamond electrode was selected as the substrate for modification and the procedure was applied to the real sample analysis including water sample (certified reference material) and wastewater sample. Using the standard addition method the concentrations of particular heavy metals were quantified and the determined values were in a good agreement with those obtained by the reference method — high resolution atomic absorption spectroscopy with electrothermal atomisation and continual radiation source. This fact highlights that the developed in situ bismuth film modified boron-doped diamond electrode is a suitable electrochemical sensor to be applied to routine analysis of water samples containing heavy metals.

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Efficacy of Intestinal Scraping Technique in the Detection of Echinococcus Multilocularis - Estimation of the Limit of the Detection and Comparison with Sedimentation and Counting Technique

.: Predictive values and quality control of techniques for the diagnosis of Echinococcus multilocularis in definitive hosts. Acta Tropica 2003, 85 , 157-163. 7. Hofer S., Gloor S., Muller U., Mathis A., Hegglin D., Deplazes P.: High prevalence of Echinococcus multilocularis in urban red foxes ( Vulpes vulpes ) and voles ( Arvicola terrestris ) in the city of Zurich, Switzerland. Parasitology 2000, 120 , 135-142. 8. Karamon J, Sroka J, Cencek T.: Limit of detection of sedimentation and counting technique (SCT) for Echinococcus

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Method validation for the determination of fraction of modern (F14C) in wood samples using conventional method

demonstrate whether the method is appropriate for its intended use ( Magnusson and Ornemark, 2014 ) as well as to prove the qualification, performance and competency. Internal method validation was expressed in terms of trueness, repeatability (within run precision), reproducibility (between run precision), limit of detection, minimum detectable activity and combined uncertainty calculation. As our radiocarbon laboratory is interested to study the impact of human activities on the ecosystem using the radiocarbon content in tree leaves as pollution biomarker, it was

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The Quantitative Determination of Insecticides in Tobacco and Tobacco Smoke. 2nd Report: The Determination of Carbamate Residues - Methoden zur quantitativen Bestimmung von Insektiziden in Tabak und Tabakrauch. II. Mitteilung: Zur Bestimmung von Carbamat-Insektiziden

Abstract

A thin-layer chromatographic method has been developed for the qualitative and quantitative determination of carbamate residues on tobacco. The method's inferior limit of detection is 80 ng for Carbaryl and 200 ng for Undene. The coefficient of variation of the results is 5.3 % for Carbaryl and 7.7 % for Undene.

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A single-step multiplex quantitative real time polymerase chain reaction assay for hepatitis C virus genotypes

for genotype-4, 25 for genotype-5 and 26 for genotype-6, respectively. The lower limit of detection (LOD) using control plasmid was found to be 176 copies/mL for genotypes 1, 2 & 3 and 167 copies/mL for genotypes 4, 5 & 6, respectively (Table 3) . The dynamic range for all singleplex assays was found to be 10 1 to 10 8 DNA plasmid copies per microliter. The concentration of DNA plasmid beyond this range could not show Cq values in the desired range of 10 - 35 cycles. This demonstrates that the DNA plasmid used in all our standard curves falls in a range suitable

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The Application of a Cadmium Reducer and a Diazotisation Reaction for the Determination of Nitrate and Nitrite in Tobacco / Über die Anwendung des Cadmium-Reduktors und der Diazotierung zur Bestimmung von Nitrat und Nitrit im Tabak

Abstract

Nitrate is reduced by means of a cadmium reducer and spectrophotometrically determined in the form of nitrite by a diazotisation reaction. The results obtained by application of the described method to tobacco extracts correspond well to those resulting from the earlier described dimethylphenol procedure. Owing to its better sensitivity and specifity the reduction method is particularly suitable for the quantitative analysis of smallest amounts of nitrate. Quantities of 0.03 % of nitrate can be determined without difficulties. The inferior limit of detection is 0.001 %.

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