Synthesis of CdTe/Fe3O4 for Quantitative Detection of BSA

2013 ◽  
Vol 446-447 ◽  
pp. 45-49
Author(s):  
Xiu Pei Yang ◽  
Xiao Cui Yang ◽  
Yu Li Fu ◽  
Xiu Mei Cheng ◽  
Zhi Jing Tan
Keyword(s):  
Ph Value ◽  
Limit Of Detection ◽  
Quantitative Detection ◽  
Relative Fluorescence Intensity ◽  
Optimal Conditions ◽  
Selective Determination ◽  
Straight Line ◽  
Line Equation ◽  
Effects Of Ph

A new kind of functionalized CdTe/Fe3O4was synthesized for the quantitative and selective determination of bovine serum albumin (BSA). The effects of pH value, reaction time, temperature and dosage of CdTe/ Fe3O4on the detection of BSA were investigated. Under optimal conditions, the straight line equation: F/F0=1.40412+0.07216 C (μmol/L) was found between the relative fluorescence intensity and the concentration of BSA in the range of 0.69-5.52 μmol/L, and the limit of detection was 0.18 μmol/L.

scholarly journals A novel catalytic adsorptive stripping voltammetric method for the determination of germanium ultratraces in the presence of chloranilic acid and the V(IV)·HEDTA complex

2020 ◽  
Vol 24 (11-12) ◽  
pp. 2891-2899
Author(s):  
Jerzy Zarębski ◽  
Andrzej Bobrowski ◽  
Agnieszka Królicka ◽  
Julia Gonciarczyk ◽  
Vasiliki Manolopoulou ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Electrolyte Composition ◽  
Hanging Mercury Drop Electrode ◽  
Film Electrode ◽  
Optimal Conditions ◽  
Subsequent Reduction ◽  
Adsorbed State ◽  
Chloranilic Acid ◽  
Effects Of Ph

Abstract A novel, sensitive catalytic adsorptive stripping voltammetric procedure which can be used to determine trace amounts of germanium is described. The method is based on the interfacial accumulation of the complex formed by Ge(IV) and the product of the reduction of chloranilic acid on the hanging mercury drop electrode or the renewable silver amalgam film electrode, and its subsequent reduction from the adsorbed state followed by the catalytic action of the V(IV)·HEDTA complex. The presence of V(IV)·HEDTA greatly enhances the adsorptive stripping response of Ge. The reduction of the Ge(IV) in the presence of chloranilic acid and V(IV)·HEDTA was investigated in detail and the effects of pH, electrolyte composition, and instrumental parameters were studied. Under optimal conditions, the catalytic peak current of germanium exhibited good linearity for Ge(IV) concentrations in the range of 0.75–60 nM (for 60 s of accumulation at −0.1 V, r2 = 0.995) and a low limit of detection (LOD = 0.085 nM). The procedure was successfully applied to determine Ge in water samples.

Novel palladium(II) selective membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol

2010 ◽  
Vol 75 (5) ◽  
pp. 563-575 ◽  
Author(s):  
Moslem Mohammadi ◽  
Mehdi Khodadadian ◽  
Mohammad K. Rofouei
Keyword(s):  
Limit Of Detection ◽  
Membrane Electrode ◽  
Aqueous Samples ◽  
Selective Determination ◽  
Poly Vinyl Chloride ◽  
Selective Membrane ◽  
Ph Range ◽  
Palladium Content ◽  
Methyl Benzene

A plasticized poly(vinyl chloride) membrane electrode based on 4-[(5-mercapto-1,3,4-thiadiazol-2-ylimino)methyl]benzene-1,3-diol (L) for highly selective determination of palladium(II) (in PdCl42– form) is developed. The electrode showed a good Nernstian response (29.6 ± 0.4 mV per decade) over a wide concentration range (3.1 × 10–7 to 1.0 × 10–2 mol l–1). The limit of detection was 1.5 × 10–7 mol l–1. The electrode has a response time of about 20 s, and it can be used for at least 2 months without observing any considerable deviation from Nernstian response. The proposed electrode could be used in the pH range of 2.5–5.5. The practical utility of the electrode has been demonstrated by its use for the estimation of palladium content in aqueous samples.

Determination of Mimosine and 2,3-Dihydroxypyridine in Leucaena leucocephala by Reversed Phase High-Performance Liquid Chromatography

2011 ◽  
Vol 140 ◽  
pp. 296-301 ◽  
Author(s):  
Cai Mei Wu ◽  
Hong Min Yuan ◽  
Gang Jia ◽  
Zhi Sheng Wang ◽  
Xiu Qun Wu
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Leucaena Leucocephala ◽  
High Performance ◽  
Limit Of Detection ◽  
Reversed Phase ◽  
Quantitative Detection ◽  
Uv Detector ◽  
Chromatography Method

A reversed high performance liquid chromatography method was developed for the quantitative determination of mimosine and 2,3-DHP in leaves ofLeucaena Leucocephala. Mimosine and 2,3DHP were extracted using 0.1N HCl.The chromatograph conditions were investigated and optimized. The optimal HPLC conditions as follows: Agilent HC-C18 column （4.6×150mm,5μm） was used at 30°C. The method used a variable wavelength UV detector at 280nm, the mobile phase consisted of 0.2 % (w/v) orthophosphoric acid and methanol, the gradient elution was adopted. The injection volume was 10μL. The linearity is favorable in the range of 1.0 to 50μg mL-1with a correlation coefficient of 0.99998 for mimosine and 0.99902 for 2,3DHP. Under the optimal conditions, the method limit of detection (LOD) of mimosine and 2,3DHP were 0.40mg/kg and 0.55mg/kg respectively. The recovery of mimosine was 87.00-94.70% with the RSD (n=5) of 2.75-3.81% in the spiked levels 0,1, 5, 20mg/g. At the same time, the recovery of 2,3DHP was 88-95.4% with the RSD (n=5) of 2.24-4.90%. The method was found to be simple, sensitive, fast and accurate, and has been applied successfully for the quantitative detection of mimosine and 2,3-DHP in leaves ofLeucaena Leucocephala, plasma and excretion of ruminant.

Chlorobenzene. Determination in workplace air

2019 ◽  
Vol 35 (1(99)) ◽  
pp. 19-28
Author(s):  
Anna Jeżewska ◽  
Agnieszka Woźnica
Keyword(s):  
Occupational Exposure ◽  
Carbon Disulfide ◽  
Limit Of Detection ◽  
Skin Irritation ◽  
Raw Material ◽  
Good Precision ◽  
Limit Of Quantification ◽  
Selective Determination ◽  
Workplace Air

Chlorobenzene is a colorless, flammable liquid that has an almond-like odor. It is used in industry as a solvent: resins, paints and fats, raw material for the production of plastics, as well as for the production of phenol, aniline and nitrobenzene. Occupational exposure to chlorobenzene vapors can occur through inhalation, absorption through the skin or ingestion. Harmful if inhaled, causes skin irritation. Long-term exposure affects the central nervous system. The aim of this study was an amendment to the PN-Z-04022- 03:2001 withdrawn from the Polish set of standards, and validate method for determination concentrations of chlorobenzene in the workplace air in the range from 1/10 to 2 MAC values, in accordance with the requirements of the standard PN-EN 482. The study was performed using a gas chromatograph (GC) with a flame ionization detector (FID) equipped with a capillary column HP-5 (30 m x 0.32 mm, 0.25 μm). This method is based on the adsorption of chlorobenzene vapors on activated charcoal, desorption with carbon disulfide, and analyzed by GC-FID. Application of HP-5 column allows selective determination of chlorobenzene in a presence of carbon disulfide, aniline, phenol and nitrobenzene. The measurement range was 2.3 ÷ 46 mg/m3 for a 15 l air sample. Limit of detection: 6.75 ng/ml and limit of quantification: 20.25 ng/ml. Analytical method described in this paper enables selective determination of chlorobenzene in workplace atmosphere in presence of other solvents at concentrations from 2.3 mg/m3 (1/10 MAC value). The method is characterized by good precision and accuracy and meets the criteria for the performance of procedures for the measurement of chemical agents, listed in EN 482. The method may be used for the assessment of occupational exposure to chlorobenzene and the associated risk to workers’ health. The developed method of determining chlorobenzene has been recorded as an analytical procedure (see Appendix). This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering.

A spectrofluorimetric method for the determination of acitretin in pharmaceuticals

2009 ◽  
Vol 63 (4) ◽  
Author(s):  
Suling Feng ◽  
Yi Zhang ◽  
Jing Fan
Keyword(s):  
Fluorescence Spectra ◽  
Hplc Method ◽  
Relative Fluorescence Intensity ◽  
Optimum Conditions ◽  
Green Fluorescence ◽  
Spectrofluorimetric Method ◽  
Highly Sensitive ◽  
Relative Standard ◽  
Effects Of Ph

AbstractA simple, rapid, and highly sensitive spectrofluorimetric method for the determination of acitretin was developed based on the strong green fluorescence of acitretin. Influence of organic solvents on the fluorescence spectra of acitretin was studied. Effects of pH, standing time, and foreign ions on the determination of acitretin were also examined. Under the optimum conditions, linear relationship between the relative fluorescence intensity and the concentration of acitretin in the range of 30.0–1100 ng mL−1 was obtained. Detection limit of this method is 9.56 ng mL−1 for acitretin. Relative standard deviation for the determination of 480 ng mL−1 of acitretin was 1.70 %. This method was used for the determination of acitretin in pharmaceuticals and the results were compared with those obtained by the HPLC method.

scholarly journals Determination of Methadone and Tramadol in Vitreous Humor Specimens Using Dispersive LiquidLiquidMicroextractionandUltraHighPerformance Liquid Chromatography

2021 ◽  
Vol 11 (1) ◽  
pp. 31530.1-31530.9
Author(s):  
Maryam Akhgari ◽  
Keyword(s):  
Liquid Chromatography ◽  
Ph Value ◽  
Limit Of Detection ◽  
Vitreous Humor ◽  
Point Of View ◽  
Limit Of Quantification ◽  
Ultrahigh Performance Liquid Chromatography ◽  
Abused Drugs ◽  
Dispersive Liquid Liquid Microextraction

Background: Drug abuse is spreading rapidly all over the world. Methadone and tramadol are among not only the most abused opioids but also important from the forensic point of view. Therefore, we need to devise a simple and sensitive method for the sample preparation and identification of abused drugs in postmortem specimens. Methods: A simple and rapid Dispersive Liquid-Liquid Microextraction (DLLME) technique coupled with Ultrahigh Performance Liquid Chromatography (UHPLC) was developed for the extraction and analysis of methadone and tramadol from postmortem vitreous humor samples. Different parameters affecting the extraction recovery, such as the type and volume of extraction and dispersion solvents, pH value, sensitivity, and specificity, were optimized and studied. Results: Under optimized conditions, the recovery ranges were 82.3%-89.6% and 85.4%-87.1% for methadone and tramadol, respectively. The linear range was 25-100 ng/mL for both methadone and tramadol with a correlation coefficient (R2) of more than 0.98. Limit of Detection (LoD) and Limit of Quantification (LoQ) were 3 and 8 ng/mL for methadone and 6 and 16 ng/mL for tramadol. The accuracy level of the methods for methadone and tramadol detection were 99.4%-100% and 99.7%-99.9%, respectively. The method was specific enough for the qualitative and quantitative determination of methadone and tramadol. Conclusion: The obtained results showed that DLLME combined with UHPLC is a fast and straightforward method for determining methadone and tramadol in postmortem vitreous humor specimens.

scholarly journals Development of membrane electrodes for selective determination of lisinopril in pharmaceuticals

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Nagaraju Rajendraprasad ◽  
Kanakapura Basavaiah
Keyword(s):  
Enzyme Inhibitor ◽  
Limit Of Detection ◽  
Low Cost ◽  
Ion Pairs ◽  
Standard Addition ◽  
Phosphomolybdic Acid ◽  
Selective Determination ◽  
Accuracy And Precision ◽  
Selective Membrane

Abstract Background Lisinopril (LNP) is an angiotensin-converting enzyme inhibitor used as anti-hypertensive, cardiovascular, in anti-prophylactic and anti-diabetic nephropathy drug. Development of two new, simple, low cost, and selective membrane-based ion-selective electrodes has been proposed for the determination of LNP in pharmaceuticals. Methods The electrodes are based on poly(vinyl)chloride membrane doped with LNP-phosphotungstic acid (LNP-PTA) and LNP-phosphomolybdic acid (LNP-PMA) ion-pairs as molecular recognition materials. Results The developed LNP-PTA and LNP-PMA electrodes are applicable for the determination of LNP over the linear range of 5 × 10−5–2.4 × 10−3 mol l−1. The working pH ranges to measure potentials were 2.5 to 6.4 and 2.3 to 6.0 for LNP-PTA and LNP-PMA ISEs, respectively. The electrodes displayed the rapid Nernstian responses as revealed by the values of slopes 55.06 and 52.39 mV/decade, with limit of detection (LOD) values of 1.2 × 10−5 and 1.18 × 10−5 mol l−1 for LNP-PTA and LNP-PMA electrodes, respectively. The limits of quantitation (LOQ) values have also been calculated for both the electrodes. The developed electrodes have potential stability for up to 1 month and emerged as highly selective for the determination of LNP over other spiked ions and compounds. Conclusions The proposed electrodes have been validated and found that they are suitable for the determination of LNP in pharmaceuticals in pure form and in dosage forms. The results obtained in the analysis of LNP using proposed electrodes have been compared statistically with reference method’s results to assess the accuracy and precision. Robustness and ruggedness of the developed electrodes have also been checked and found satisfactory. The recovery studies have been performed by standard addition procedure to assess the role of excipients in tablets containing LNP and the results obtained are satisfactory.

scholarly journals Determination of fumonisins B1 and B2 in beer

2011 ◽  
Vol 23 (No. 1) ◽  
pp. 20-26 ◽  
Author(s):  
Ľ. Daško ◽  
D. Rauová ◽  
E. Belajová ◽  
M. Kováč
Keyword(s):  
Fluorescence Detection ◽  
Phosphate Buffer ◽  
Analytical Procedure ◽  
Ph Value ◽  
Limit Of Detection ◽  
Gradient Elution ◽  
Cleaning Procedure ◽  
Peak Splitting

The aim of this study was to investigate the contamination of beer of Slovak origin with fumonisins. A suitable analytical procedure was suggested &ndash; the limit of detection at the level close to 1 &micro;g/l was achieved for both fumonisins B<sub>1</sub> and B<sub>2</sub>. The recovery was determined at 93% for fumonisin B<sub>1 </sub>and at 78% for fumonisin B<sub>2</sub>. Fluorescence detection was used after derivatisation with a mixture of o-phthaldialdehyde and 2-mercaptoethanol. Phosphate buffer usually applied resulted in a poor separation of derivatised fumonisins. Peak splitting was observed depending on the pH of the eluent. The pH value of 2.6 was found suitable for the peak splitting elimination. A convenient gradient elution metod was suggested avoiding the possible interference in fumonisin contents determination. For the preparation of samples, immunoaffinity cleaning procedure was applied. Beer samples from all domestic producers were analysed. The content of fumonisins determined was under the limit of detection in all cases. All the beers tested were produced from the barley grown in 2003. &nbsp;

A Novel Fluorescent Nanoswitch Based on Carbon Dots for Sensitive Detection of Hg2+ and I−

NANO ◽  
2017 ◽  
Vol 12 (02) ◽  
pp. 1750024 ◽  
Author(s):  
Xiqing Liu ◽  
Xiao Wei ◽  
Yeqing Xu ◽  
Hongji Li ◽  
Kai Lu ◽  
...  
Keyword(s):  
Linear Relationship ◽  
Fluorescence Intensity ◽  
Carbon Dots ◽  
Limit Of Detection ◽  
Hydrothermal Process ◽  
Fluorescence Emission ◽  
Selective Determination ◽  
Fluorescence Switching ◽  
Interfering Ions

In this paper, a novel fluorescent nanoswitch based on carbon dots (CDs) was developed for the sensitive and selective determination of Hg[Formula: see text] and I[Formula: see text]. The CDs were obtained by simple hydrothermal process and had a strong fluorescence emission at 440[Formula: see text]nm. The fluorescence of the CDs can be selectively quenched by Hg[Formula: see text] ion, and then the I[Formula: see text] was added into the system, which can interact with Hg[Formula: see text] and recover fluorescence of the CDs. Under optimal conditions, the quenching fluorescence intensity on addition of Hg[Formula: see text] has obtained a satisfactory linear relationship covering the linear range of 0–50[Formula: see text][Formula: see text]M with the linear relationship ([Formula: see text]), and the limit of detection is 0.047[Formula: see text][Formula: see text]M. The additions of I[Formula: see text] could lead to the fluorescence intensity of the solution of CDs and Hg[Formula: see text] (50[Formula: see text][Formula: see text]M) recover rapidly, which is linearly related ([Formula: see text]) to the concentration of I[Formula: see text] in the range from 0 to 70[Formula: see text][Formula: see text]M, the detection limit for I[Formula: see text] was calculated to be 0.084[Formula: see text][Formula: see text]M. Moreover, the developed method to detect Hg[Formula: see text] and I[Formula: see text] was evaluated in real examples, and the fluorescence switching can sensitively and selectively detect Hg[Formula: see text] and I[Formula: see text] over some potentially interfering ions, the recoveries were up to 97.8–107.0% and 96.7–106.6%, respectively.

1,2-Dichloroethane. Determination in workplace air

2018 ◽  
Vol 34 (2(96)) ◽  
pp. 133-143
Author(s):  
Agnieszka Woźnica
Keyword(s):  
Limit Of Detection ◽  
Flammable Liquid ◽  
Limit Of Quantification ◽  
Selective Determination ◽  
Flame Ionization ◽  
Chemical Agents ◽  
Workplace Air ◽  
Other Substances ◽  
Air Sample

1,2-Dichloroethane is a colorless, highly flammable liquid with a chloroform-like odor. This substance is used in industry as an intermediate in the production of vinyl chloride, but it is also used in the production of other chlorinated hydrocarbons. It is also used as a solvent. 1,2-Dichloroethane is carcinogenic for humans. The aim of this study was to develop a method for determining concentrations of 1,2-dichloroethane in the workplace air in the range from 1/10 to 2 MAC values (0.82–16.4 mg/m3). The study was performed using a gas chromatograph (GC) with a flame ionization detector (FID) equipped with a capillary column HP-1 (50 m x 0.32 mm; 0.3 μm). The method is based on the adsorption of 1,2-dichloroethane on activated charcoal, desorption of analyzed compound with carbon disulfide and analysis of obtained solution with GC-FID. The use of HP-1 column enabled selective determination of 1,2-dichloroethane in a presence of other substances. The average desorption coefficient of 1,2-dichloroethane from charcoal was 0.98. The method is linear (r = 0.9999) within the investigated working range from 9.84 to 196.8 μg/ml, which is equivalent to air concentrations from 0.82 to 16.4 mg/m3 for a 12-L air sample. The limit of detection (LOD) and limit of quantification (LOQ) were to 2.284 μg/ml and 6.85 μg/ml, respectively. The analytical method described in this paper enables selective determination of 1,2-dichloroethane in workplace air in presence of other substances at concentrations from 0.82 mg/m3 (1/10 MAC value). The method is precise, accurate and it meets the criteria for procedures for measuring chemical agents listed in Standard No. EN 482. The method can be used for assessing occupational exposure to 1,2-dichloroethane and associated risk to workers’ health. The developed method of determining 1,2-dichloroethane has been recorded as an analytical procedure (see appendix).

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