Detection of peroxyacetyl nitrate in air using chemiluminescence aerosol detector

2014 ◽  
Vol 68 (11) ◽  
Author(s):  
Pavel Mikuška ◽  
Lukáš Bružeňák ◽  
Zbyněk Večeřa
Keyword(s):  
Alkaline Solution ◽  
Limit Of Detection ◽  
Packed Column ◽  
Direct Reaction ◽  
Peroxyacetyl Nitrate ◽  
Brij 35 ◽  
Alternative Approach ◽  
Sensitive Determination ◽  
Triton X

AbstractA method for the rapid and sensitive determination of peroxyacetyl nitrate (PAN) in air based on a chemiluminescence reaction with an alkaline solution of luminol in the chemiluminescence aerosol detector is described. The PAN is chromatographically separated from nitrogen dioxide and ozone in a packed column filled with 5 % OV-1 on Chromosorb 30/60 and the eluted PAN is detected via the direct reaction with the luminol solution consisting of 0.002 mol L−1 luminol, 1 vol. % Brij-35 and 0.1 mol L−1 KOH. The limit of detection is 14.9 ng m−3 (3 ppt) of PAN. Alternatively, the PAN after separation is thermally converted to NO2 which is detected by the chemiluminescence reaction with a solution consisting of 0.002 mol L−1 luminol, 0.5 mol L−1 KOH, 0.2 mol L−1 Na2SO3, 0.1 mol L−1 KI, 0.05 mol L−1 EDTA and 0.5 vol. % triton X-100. The alternative approach affords the simultaneous determination of PAN and NO2. The limit of detection is 50 ppt of PAN and 50 ppt of NO2. The time resolution is 3 min. The method was applied to the measurement of ambient peroxyacetyl nitrate in air.

Spectrophotometric study of the complexation equilibria of cadmium ions with 5-bromo and 5-chloro derivatives of 2-(2-pyridylazo)-5-diethylaminophenol (BrPADAP, ClPADAP)

1983 ◽  
Vol 48 (1) ◽  
pp. 52-59 ◽  
Author(s):  
Vlastimil Kubáň ◽  
Miroslav Macka
Keyword(s):  
Equilibrium Constants ◽  
Spectrophotometric Study ◽  
Graphical Analysis ◽  
Optimal Conditions ◽  
Cadmium Ions ◽  
Brij 35 ◽  
Ethanol Medium ◽  
Triton X ◽  
Derivatives Of

The composition, optical characteristics, molar absorption coefficients and equilibrium constants of the reactions of formation of the ML and ML2 complexes of both reagents with cadmium(II) ions were determined by graphical analysis and numerical interpretation of the absorbance-pH curves by the modified SQUAD-G program. Optimal conditions were proposed for the spectrophotometric determination of Cd in 10% v/v ethanol medium in the presence of 0.1% w/v Triton X-100 or 1% w/v Brij 35. BrPADAP and ClPADAP are the most sensitive spectrophotometric reagents for the determination of cadmium(II) ions (ε = 1.28-1.44 . 105 mmol-1 cm2 at 560 nm and pH 8.0-9.5) with a high colour contrast in the reaction (Δλmax ~117 nm) and a selectivity similar to that of other N-heterocyclic azodyes (PAR, PAN, etc.).

scholarly journals Immobilization-Free Electrochemical Sensor Coupled with a Graphene-Oxide-Based Aptasensor for Glycated Albumin Detection

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 85
Author(s):  
Wassa Waiwinya ◽  
Thitirat Putnin ◽  
Dechnarong Pimalai ◽  
Wireeya Chawjiraphan ◽  
Nuankanya Sathirapongsasuti ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensor ◽  
Detection Method ◽  
Limit Of Detection ◽  
Glycated Albumin ◽  
Cost Effective ◽  
Logarithmic Scale ◽  
Electrochemical Aptasensor ◽  
Alternative Approach

An immobilization-free electrochemical sensor coupled with a graphene oxide (GO)-based aptasensor was developed for glycated human serum albumin (GHSA) detection. The concentration of GHSA was monitored by measuring the electrochemical response of free GO and aptamer-bound GO in the presence of glycated albumin; their currents served as the analytical signals. The electrochemical aptasensor exhibited good performance with a base-10 logarithmic scale. The calibration curve was achieved in the range of 0.01–50 µg/mL. The limit of detection (LOD) was 8.70 ng/mL. The developed method was considered a one-drop measurement process because a fabrication step and the probe-immobilization process were not required. This simple sensor offers a cost-effective, rapid, and sensitive detection method, and could be an alternative approach for determination of GHSA levels.

Determination of Phytosterols in Butter Samples by Using Capillary Column Gas Chromatography

1987 ◽  
Vol 70 (5) ◽  
pp. 912-915 ◽  
Author(s):  
Randall L Smith ◽  
Darryl M Sullivan ◽  
Earl F Richter
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Retention Time ◽  
Capillary Column ◽  
Limit Of Detection ◽  
Packed Column ◽  
Gas Chromatography Mass Spectrometry ◽  
Positive Bias ◽  
Capillary Column Gas Chromatography

Abstract A positive bias in the gas chromatographic (GC) analysis of butter for β-sitosterol was discovered when attempting to confirm values by gas chromatography/mass spectrometry (GC/MS). The source of the problem was traced to an interfering material that was not effectively separated by packed column GC. Because capillary columns are known to provide superior separation, they were substituted for packed columns in the assay, and instrument parameters were modified accordingly. A compound with a similar retention time, identified by GC/MS as lanosterol, was separated from β-sitosterol by the capillary column. The capillary column technique was applied to over 300 butter samples. The results indicate that the method can accurately quantitate β-sitosterol in butter with no known interferences. The limit of detection for this method is 1 mg/100 g. Recoveries at a level of 3 mg/100 g averaged 98% with a coefficient of variation of 3.45%

Sensitive Determination of Epinephrine in the Presence of Ascorbic Acid at Poly(diphenylamine sulfonic acid) Modified Sensor

2020 ◽  
Vol 18 (4) ◽  
pp. 253-258
Author(s):  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Sulfonic Acid ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Pulse Voltammetry ◽  
Modified Sensor

A sensitive and simple modified sensor was prepared by electrodeposition of diphenylamine sulfonic acid (DPSA) to the glassy carbon electrode surface by cyclic voltammetry (CV) technique. The electrooxidation of epinephrine (EP) was accomplished by CV and differential pulse voltammetry at poly(DPSA) modified sensor. As a result of the findings, the current values were enhanced and both substances were separated at the modified sensor compared to the bare electrode. There was linearly between the oxidation current and concentration of EP from 0.2 to 100 μM in phosphate buffer solution at pH 7.0. The limit of detection was 5.0 nM and the sensitivity was 0.4205 μA/μM. The determination of EP was successfully and satisfactorily carried out in real samples such as human blood serum and urine at the poly(DPSA) sensor. To the best knowledge of this work, this is the first study that detect the EP in the presence of ascorbic acid at poly(DPSA) sensor in the literature.

scholarly journals Improvement of a 'SSQuEE' Method for Recovery and Preconcentration of Pesticides from Environmental Samples

2021 ◽  
Vol 33 (10) ◽  
pp. 2472-2476
Author(s):  
Rajib Joarder
Keyword(s):  
Cloud Point ◽  
High Performance ◽  
Limit Of Detection ◽  
Ionic Surfactant ◽  
Analytical Technique ◽  
Liquid Chromatography Separation ◽  
Cloud Point Temperature ◽  
Triton X ◽  
Optimum Extraction

A simple, sensitive, quick, easy and efficient (SSQuEE) analytical technique based on cloud point extraction (CPE) has been developed for the determination of different pesticides present in soil and water with high performance liquid chromatography separation and ultraviolet detection. The environmentally friendliness surfactant like Triton X -100, compared to Tween series of non-ionic surfactant can effectively extract imidacloprid (insecticide), flusilazole (fungicide) and atrazine (herbicide) at cloud point temperature at 67 ºC, 82 ºC and 62 ºC, respectively. To reach the optimum extraction efficiency, different experimental parameters like surfactant concentration, salt type and its concentration, equilibrium time and temperature, pH were observed. At the optimum conditions, linear regression coefficient of the standard curves was greater than 0.9924. The limit of detection of imidacloprid, flusilazole and atrazine were 0.10 μg L-1, 0.24 μg L-1, 0.15 μg L-1 and recovery percent are 99.71 %, 88.1% and 89.74%, respectively.

scholarly journals Headspace Gas Chromatographic Determination of 1,3-Butadiene in Simulated Saliva

2000 ◽  
Vol 83 (4) ◽  
pp. 929-932 ◽  
Author(s):  
Shirley Abrantes ◽  
Tereza C Dos Santos ◽  
Grazieli SimÕES
Keyword(s):  
Limit Of Detection ◽  
Chromatographic Determination ◽  
Calibration Graph ◽  
Chewing Gum ◽  
Preliminary Assessment ◽  
Headspace Gas ◽  
Sensitive Determination ◽  
Headspace Gc ◽  
Migration Limit

Abstract A headspace gas chromatographic (GC) method was developed to determine 1,3-butadiene (1,3-BD) in simulated saliva in contact with chewing gum. The calibration graph was linear, and the limit of detection was 0.004 mg/L, which is well below the migration limit for this substance. The headspace GC method provides rapid and reliable analysis for monitoring 1,3-BD migration from chewing gum into simulated saliva. In this paper, we report headspace methodology for sensitive determination of 1,3-BD in chewing gum and results of selected analyses, enabling preliminary assessment of possible exposure to 1,3-BD through migration.

Simultaneous gas-chromatographic analysis for phenobarbital, diphenylhydantoin, carbamazepine, and primidone in serum.

1976 ◽  
Vol 22 (6) ◽  
pp. 769-771 ◽  
Author(s):  
C V Abraham ◽  
H D Joslin
Keyword(s):  
Chromatographic Analysis ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Peak Height ◽  
Gas Liquid Chromatography ◽  
Toxic Concentration ◽  
Sensitive Determination ◽  
Derivatives Of ◽  
Methyl Phenyl

Abstract We describe a simple, sensitive determination of phenobarbital, diphenylhydantoin, carbamazepine, and primidone in serum, by use of gas-liquid chromatography with temperature programming. The methylated derivatives of these anticonvulsants are well resolved, as was 5-(p-methyl-phenyl)-5-phenylhydantoin, the internal standard. The proposed procedure requires only 0.20 ml of serum and can be done in less than 30 min. The lower limit of detection for each of the drugs is 0.5 mg/liter. Analytical recoveries of drug from serum were excellent and peak height and concentration were linearly related up to twice the toxic concentration for serum.

scholarly journals Micellar LC Separation of Sesquiterpenic Acids and Their Determination in Valeriana officinalis L. Root and Extracts

2012 ◽  
Vol 2012 ◽  
pp. 1-8
Author(s):  
Artem U. Kulikov
Keyword(s):  
Mobile Phase ◽  
Limit Of Detection ◽  
Micellar Liquid Chromatography ◽  
Valeriana Officinalis ◽  
Solution Ph ◽  
Hydroalcoholic Extract ◽  
Brij 35 ◽  
Ich Guidelines ◽  
Valerenic Acids

A simple micellar liquid chromatography (MLC) method was developed and validated according to ICH Guidelines for the determination of sesquiterpenic acids (valerenic, hydroxyvalerenic, and acetoxyvalerenic acids) in root and rhizome extract from Valeriana officinalis L. and valerian dry hydroalcoholic extract. Samples were analyzed on Nucleosil C18 column (, 5 μm) using an isocratic mobile phase which consisted of Brij 35 (5% (w/v) aqueous solution; pH  by phosphoric acid) and 1-butanol (6% (v/v)); UV detection was at 220 nm. Micellar mobile phase using allows to fully separate valerenic acids within 25 minutes. Linearity for hydroxyvalerenic, acetoxyvalerenic, and valerenic acids was 1.9–27.9, 4.2–63.0, and 6.1–91·3 μg.mL−1, and limit of detection was 0.14, 0.037, and 0.09 μg·mL−1, respectively. Intraday and interday precisions were not less than 2% for all investigated compounds. The proposed method was found to be reproducible and convenient for quantitative analysis of sesquiterpenic acids in valerian root and related preparations.

scholarly journals Melamine Recognition: Molecularly Imprinted Polymer for Selective and Sensitive Determination of Melamine in Food Samples

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Mohadese Biabani ◽  
Azizollah Nezhadali ◽  
Ahmad Nakhaei ◽  
Hossein Nakhaei
Keyword(s):  
Limit Of Detection ◽  
Electrochemical Techniques ◽  
Food Samples ◽  
Quantitative Measurements ◽  
Sensitive Determination ◽  
Burman Design ◽  
Mip Sensor ◽  
Optimized Conditions ◽  
Plackett Burman Design

In this study, a sensitive and selective sensor is constructed to measure the melamine (MEL) using molecular imprinting polymer (MIP) technique. Chemical and electrochemical techniques are used to construct the MIP and quantitative measurements. The constructed sensor was modified with GO-Fe3O4@SiO2 nanocomposite. Screening and optimization of factors are done using statistical methods, including Plackett–Burman design (PBD) and central composite design (CCD). Under the optimized conditions, an MIP sensor showed a linear range from 5.0 × 10−7 to 1.0 × 10−5 M MEL concentration with a correlation coefficient (R2) of 0.9997. The limit of detection was obtained (0.028 µM) with a highly reproducible response (RSD 2.15%, n = 4). The electrochemical sensor showed good results for the determination of MEL in food samples.

scholarly journals Micelle-Mediated Extraction Prior to LC-UV for Preconcentration and Determination of Trace Amounts of Bisphenol A in Environmental Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Naghi Saadatjou ◽  
Shahab Shariati ◽  
Mostafa Golshekan
Keyword(s):  
Bisphenol A ◽  
High Performance ◽  
Limit Of Detection ◽  
Aqueous Samples ◽  
Limit Of Quantification ◽  
Rich Phase ◽  
Factors Affecting ◽  
Relative Standard ◽  
Triton X

A simple and high sensitive preconcentration method based on micelle-mediated extraction followed by high performance liquid chromatography (LC-UV) was developed for preconcentration and determination of trace amounts of bisphenol A (BPA) in aqueous samples. The BPA was quantitatively extracted from aqueous samples in the presence of Triton X-114 as a nonionic surfactant and preconcentrated into the small volume (about 30 μL) of the surfactant-rich phase. Taguchi method, an orthogonal array design (OA16 (45)), was utilized to optimize the various factors affecting the micellar extraction of BPA. The maximum extraction efficiency of BPA was obtained at pH 3, 0.2% (w/v) Triton X-114, and 0.25 mol L−1 sodium acetate. For the preconcentration, the solutions were incubated in a thermostatic water bath at 50°C for 7 min. After centrifuge and separation of aqueous phase, the surfactant-rich phase was diluted with 100 μL acetone and injected in the chromatographic system. Under the optimum conditions, preconcentration factor of 34.9 was achieved for extraction from 10 mL of sample solution and the relative standard deviation (RSD%) of the method was lower than 6.6%. The calibration curve was linear in the range of 0.5–150 μg L−1 with reasonable linearity (r2>0.9987). The limit of detection (LOD) based on S/N = 3 was 0.13 μg L−1 for 10 mL sample volumes. The limit of quantification (LOQ) based on S/N = 10 was 0.43 μg L−1 for 10 mL sample volumes. Finally, the applicability of the proposed method was evaluated by the extraction and determination of BPA in the real samples, and satisfactory results were obtained.

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