Laser optoacoustic detection of trace concentration levels of ethylene, vinylchloride, and styrene in the atmosphere

1989 ◽  
Vol 54 (10) ◽  
pp. 2667-2673 ◽  
Author(s):  
Vojtěch Steiner ◽  
Pavel Engst ◽  
Zdeněk Zelinger ◽  
Milan Horák
Keyword(s):  
Detection Limit ◽  
Emission Line ◽  
Laser Line ◽  
Laser Source ◽  
Trace Concentration ◽  
Selective Determination ◽  
Hygienic Standard ◽  
Trace Concentrations ◽  
Concentration Levels

The optoacoustic analyzer with a tunable CO2 laser source employed in the present work permits a selective determination of ethylene in trace concentrations higher than 5 ppb (=detection limit for the 10P(14) emission line of the CO2 laser, ν = 949.5 cm-1) and of vinylchloride higher than 42 ppb (= detection limit for the 10P(22) CO2 laser line, ν= 942.4 cm-1). this method covers for both compounds the concentration range corresponding to the hygienic standard. It can be also used for the determination of styrene vapour with concentrations higher than 1.5 ppm.

scholarly journals Selective Determination of Iron(III) in Sea Water by Gold Nanoparticles Self-assembled with N-carboxyl- L-cysteine

2014 ◽  
Vol 17 (1) ◽  
pp. 001-004 ◽  
Author(s):  
Benzhi Liu ◽  
Min Wang
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Sea Water ◽  
Stripping Voltammetry ◽  
Differential Pulse ◽  
Operational Parameters ◽  
Selective Determination ◽  
Self Assembled ◽  
Optimized Conditions

Application of gold nanoparticles self-assembled with N-carboxyl- L-cysteine for the determination of iron(III) was investigated. Differential pulse adsorptive stripping voltammetry was used to detect iron(III). Various operational parameters were investigated and discussed in terms of their effects on the measurement signals. A linear range from 0.1 nM to 1.8 nM with a detection limit of 0.03 nMwas obtained under optimized conditions. The applicability of the method was successfully tested by determination of iron(III) in sea water samples.

Imidazole-appended 9,10-anthracenedicarboxamide probe for sensing nitrophenols and selective determination of 2,4,6-trinitrophenol in an EtOH–water medium

RSC Advances ◽  
2016 ◽  
Vol 6 (73) ◽  
pp. 68627-68637 ◽  
Author(s):  
Anup Pandith ◽  
Ashwani Kumar ◽  
Hong Seok Kim
Keyword(s):  
Detection Limit ◽  
Water Medium ◽  
Selective Determination ◽  
Low Detection Limit

A novel imidazole-appended anthracenedicarboxamide probe (AIM-D) discriminated TNP among nitrophenols based on ratiometric response in 1 : 1 EtOH–H2O with a very low detection limit of 1 nM.

scholarly journals A Rapid and Selective Method for Determining Potential Nitrosating Agents in Cosmetic Products by Chemiluminescence Detection of Nitric Oxide

1998 ◽  
Vol 81 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Hardy J Chou ◽  
Ronald L Yates
Keyword(s):  
Nitric Oxide ◽  
Detection Limit ◽  
False Positive ◽  
Nitroso Compounds ◽  
Cosmetic Products ◽  
Chemiluminescence Detection ◽  
Selective Method ◽  
Selective Determination ◽  
Chemiluminescent Reaction

abstract A method was developed for rapid and selective determination of potential nitrosating agents at the part-per-billion level in cosmetic products. These compounds are chemically reduced to nitric oxide, which is determined by its chemiluminescent reaction with ozone. Suspended materials and colors in cosmetic products do not interfere. Hence their removal before analysis is not required. A detection limit of 33 ppb, calculated as nitrite, was obtained. No false-positive interferences were observed from antifoaming agents, several AZ-nitroso compounds, and nitrate up to 20 ppm. Among cosmetic products surveyed, potential nitrosating agents were found at levels ranging from 113 to 5021 ppb. No consistent relationship was found between levels of potential nitrosating agents and N-nitrosamines in the same products. However, the highest levels of nitrosating agents were most often associated with the highest levels of N-nitrosamines known to be present in the products.

Molecularly imprinted electrochemical sensor for selective determination of oxidized glutathione

2015 ◽  
Vol 7 (5) ◽  
pp. 2210-2214 ◽  
Author(s):  
Hong Hai ◽  
Xiaodong An ◽  
Jianping Li
Keyword(s):  
Detection Limit ◽  
Electrochemical Sensor ◽  
The Other ◽  
Oxidized Glutathione ◽  
Molecularly Imprinted ◽  
Selective Determination

A molecularly imprinted sensor was prepared for the selective determination of oxidized glutathione with a detection limit of 1.8 × 10−9 mol L−1, which was lower than most of the other methods.

Determination of Ethylenethiourea in Grapes and Wine

1985 ◽  
Vol 68 (4) ◽  
pp. 741-745
Author(s):  
Jana Chovancova ◽  
Eva Matisova ◽  
Vojtech Batora
Keyword(s):  
Gas Chromatography ◽  
Detection Limit ◽  
Electron Capture ◽  
Paper Chromatography ◽  
Capillary Gas Chromatography ◽  
Electron Capture Detection ◽  
Flame Ionization Detection ◽  
Flame Ionization ◽  
Concentration Levels

Abstract Residues of ethylenethiourea (ETU) in grapes and wine were deter- [ mined by capillary gas chromatography and paper chromatography, without a cleanup step, and after derivatization to 5-benzyl-ETU. The ! detection limit was 0.0002 mg/kg for flame ionization detection, 0.008 mg/kg for paper chromatography with photodensitometric evaluation of the detected spot. Results were compared with a generally used GC method specifying electron capture detection of trifluoroacetylated S- benzyl-ETU. The recoveries of ETU in grapes and wine at different j concentration levels were determined. ETU residues were determined J in treated grapes but no residues were detected in wine

Sensitive and highly selective determination of vitamin B1 in the presence of other vitamin B complexes using functionalized gold nanoparticles as fluorophore

RSC Advances ◽  
2015 ◽  
Vol 5 (62) ◽  
pp. 49920-49925 ◽  
Author(s):  
Sekar Shankar ◽  
S. Abraham John
Keyword(s):  
Gold Nanoparticles ◽  
Detection Limit ◽  
Vitamin B1 ◽  
Vitamin B ◽  
Selective Determination ◽  
Functionalized Gold Nanoparticles ◽  
Spectrofluorimetric Determination

This work describes the spectrofluorimetric determination of thiamine in the presence of vitamin B complexes using 4-amino-6-hydroxy-2-mercaptopyrimidine as fluorophore. The detection limit was found to be 6.8 fM L−1 (S/N = 3).

scholarly journals The determination of N-methylcarbamate pesticides using enzyme immunoassays with chemiluminescent detection

2004 ◽  
Vol 22 (SI - Chem. Reactions in Foods V) ◽  
pp. S280-S282 ◽  
Author(s):  
B. Mičková ◽  
P. Rauch ◽  
A. Montoya ◽  
E. Ferri ◽  
F. Fini ◽  
...  
Keyword(s):  
Detection Limit ◽  
Matrix Effects ◽  
Colorimetric Detection ◽  
Fruit Juices ◽  
Analytical Performance ◽  
Experimental Comparison ◽  
Enzyme Immunoassays ◽  
Chemiluminescent Detection ◽  
Concentration Levels

In the present work, enzyme-linked immunosorbent assays (ELISAs) with chemiluminescent detection for the determination of carbofuran, carbaryl and methiocarb were developed and the analytical parameters of these assays were compared with those of ELISAs with colorimetric detection. The sensitivity of immunochemical methods was expressed as detection limit, linear working range, and I<sub>50</sub> value. In comparison with colorimetric ELISA, the ability of the chemiluminescent reagents to detect lower concentrations of HRP allowed to decrease the optimal antibody and conjugate concentrations and to reach better analytical parameters. The experimental comparison of the analytical performance of the ELISAs was carried out by analysing simply diluted fruit juices, spiked at different concentration levels with the above mentioned pesticides. Recovery values for both ELISAs were around 100% and no matrix effects were observed when fruit juices were diluted 1:20 or more.

Fluorimetric determination of beryllium with 3-hydroxy-2-naphthoic acid by flow injection analysis after preconcentration on a silica gel microcolumn

1989 ◽  
Vol 54 (7) ◽  
pp. 1777-1784 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Josef Havel ◽  
Bronislava Patočková
Keyword(s):  
Silica Gel ◽  
Flow Injection ◽  
Flow Injection Analysis ◽  
Fluorimetric Determination ◽  
Selective Determination ◽  
Relative Standard ◽  
Naphthoic Acid ◽  
Trace Concentrations ◽  
Certified Values

A method was worked out for the selective determination of trace concentrations of beryllium by flow injection analysis (FIA) with fluorimetric detection using 3-hydroxy-2-naphthoic acid (λex = 375 nm, λem = 455 nm) at cL = 50 μmol l-1 in 0.1M ammonium acetate, pH 7·1. In injected sample volumes of 80 μl, Be can be determined in concentrations of 10 to 156 μg l-1 with relative standard deviations not exceeding 5%, after its selective sorption on a microcolumn (2 x 40 or 3 x 30 mm) of silica gel from a medium of 0.05M-EDTA and 0.1M tartaric acid followed by elution with 0.1M-HCl. After preconcentration from 5 to 15 ml volumes, Be can be determined under the same conditions in samples at concentrations of ρBe = 0.5 to 4.6 or 0.1 to 0.8 μg l-1, respectively, with sr from 6 to 12%, the enrichment factor being as high as 200. The method was applied to beryllium bronzes and to dust from the atmosphere of the beryllium bronze foundry. The relative deviations of the beryllium content did not exceed 8% for the bronzes as compared to certified values, and 5% for the dust as compared to results obtained by ETA AAS.

scholarly journals pH Assist for Highly selective determination of Xipamide by the enhancement of the green emission of Tb3+ optical sensor

2014 ◽  
Vol 10 (5) ◽  
pp. 2720-2727 ◽  
Author(s):  
M. S. Attia ◽  
A. O. Yuossef ◽  
M. Diab ◽  
M. F. El-Shahat
Keyword(s):  
Detection Limit ◽  
Optical Sensor ◽  
Emission Band ◽  
Photophysical Properties ◽  
Green Emission ◽  
Accurate Method ◽  
Selective Determination ◽  
Pharmaceutical Tablets ◽  
Green Emission Band

The highly selective, accurate method for determination of Xipamide was maintained. The method depends on the enhancement of the green emission band of Tb3+ at 545 nm in the presence of different concentration of  Xipamide at pH 4.1 and λex = 320 nm in acetonitrile. The photophysical properties of the green  emissive Tb3+  complex have been elucidated, the terbium was used as optical sensor for the assessment of  Xipamide in the pharmaceutical tablets and body fluids with a concentration range 5.0 ×10−9 – 2.3 ×10−6 mol L−1 of xipamide, correlation coefficient of 0.995 and  detection limit of 8.5 ×10−10 mol L−1.

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