scholarly journals Amberlite XAD-2 impregnated Cyanex272: sorption desorption studies of thorium(IV)

2011 ◽  
Vol 1 (1) ◽  
pp. 83-87
Author(s):  
M. Karve ◽  
J. V. Gholave
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Flow Rate ◽  
Limit Of Detection ◽  
Phase Flow ◽  
Batch Studies ◽  
Flow Rates ◽  
Relative Standard ◽  
Impregnated Resin ◽  
Optimized Conditions

Abstract Amberlite XAD-2 impregnated with Cyanex272 was packed in a column and studied for separation and recovery of Th(IV). The effect of various parameters influencing sorption of Th(IV) viz. acid concentration, aqueous phase flow rates, nature and concentration of eluents and other ions were systematically studied. Under optimized conditions Th(IV) was quantitatively sorbed from 0.001 M HNO3 and recovered using 10 cm3 of 4.0 M HCl at 0.6 cm3 min−1 flow rate. Batch studies using impregnated resin were evaluated for using Langmuir and Freundlich adsorption isotherms. The sorption capacity of the impregnated resin for Th(IV) was 8.48 mmol g−1. The limit of detection for Th(IV) was 0.67 μg dm−3 and a reusability for more than 65 cycles was observed. The method developed was applied for isolation of Th(IV) from monazite sand. It was reproducible with a relative standard deviation (R.S.D.) of 0.8%.

Preparation of Adsorbents Based on Dendrimer Modified Silica Gel and its Adsorption Performances for Lead

2013 ◽  
Vol 800 ◽  
pp. 166-172
Author(s):  
Xiong Zhi Wu ◽  
Li Li ◽  
Fei Ping Li ◽  
Wen Ying Jin
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Silica Gel ◽  
Limit Of Detection ◽  
Modified Silica ◽  
Modified Silica Gel ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Separation And Preconcentration

A new sorbent (PAMAM4.0GASG) with gallic acid as functional group has been prepared based on G4.0 polyamidoamine dendrimer modified silica gel (PAMAM4.0SG) and characterized with FTIR. It was employed for selective separation, preconcentration and determination of lead in different samples by flame atomic absorption spectrometry (FAAS). Experimental conditions for effective separation and preconcentration of lead were optimized. The preconcentration factor reaches 200 for lead. The relative standard deviation (R.S.D.) under optimum conditions was 2.1% for 5.0 μg ml1 of Pb (II).The relative standard deviation (R.S.D.) was 2.1% for 5.0 μg ml1 of Pb (II). The limit of detection (LOD) of 0.081μg ml1 was achieved with a sample loading flow rate of 4.2 ml min1 and a 10 ml sample volume in the proposed method. The proposed column enrichment method was applied for the preconcentration/separation and determination of Pb (II) in tap water and river water samples successfully.

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

2010 ◽  
Vol 88 (6) ◽  
pp. 533-539 ◽  
Author(s):  
Larissa Zuppardo Lacerda Sabino ◽  
Daniele Cestari Marino ◽  
Horacio Dorigan Moya
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Confidence Level ◽  
Limit Of Detection ◽  
Calibration Graph ◽  
Micellar Medium ◽  
Solution Ph ◽  
Simple Method ◽  
Relative Standard

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4′-dicarboxy-2,2′-biquinoline acid. The copper(I) produced reacts with 4,4′-dicarboxy-2,2′-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 μg mL–1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 μg mL–1 (99% confidence level) and 3.5% (40 μg mL–1; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)–BCA reaction are presented as well.

scholarly journals Multiresidue Determination of Pesticides in Drinking and Related Waters by Solid-Phase Extraction and Liquid Chromatography with Ultraviolet Detection: Interlaboratory Study

2002 ◽  
Vol 85 (2) ◽  
pp. 375-383 ◽  
Author(s):  
François van Hoof ◽  
Peter van Wiele ◽  
Françoise Acobas ◽  
Jean-Luc Guinamant ◽  
Auguste Bruchet ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Solid Phase Extraction ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Tap Water ◽  
Phase Extraction ◽  
Relative Standard ◽  
Styrene Divinylbenzene

Abstract As part of a project funded by the European Commission (EC) for the development and evaluation of multiresidue methods for analysis of drinking and related waters, 17 European laboratories evaluated a method using styrene–divinylbenzene copolymer solid-phase extraction followed by liquid chromatography with diode array detection. The main aim of the study was to evaluate whether the method meets the requirements of EC Drinking Water Directive 98/83 in terms of accuracy, precision, and detection limit for 21 pesticides according to the following requirements: limit of detection, ≤0.025 μg/L; accuracy expressed as recovery, between 75 and 125%; and precision expressed as repeatability relative standard deviation of the method, <12.5%, and as reproducibility relative standard deviation of the method, <25%. Analyses for unknown concentrations were performed with commercial bottled and tap waters. All laboratories were able to achieve detection limits of 0.01 μg/L for all pesticides except pirimicarb (0.02 μg/L). The criteria for repeatability were met for all compounds. Terbutryn in bottled water and carbendazim in tap water did not meet the criteria for reproducibility. In terms of accuracy, the method met the requirements for all pesticides in both matrixes, except for metamitron. However, several compounds (linuron, terbutryn, propazine, metobromuron, and isoproturon) showed recoveries slightly below 75%.

A Novel Multifunctional Near-Infrared Absorbing Dye for Hg2+ Recognition

2013 ◽  
Vol 320 ◽  
pp. 460-464
Author(s):  
Lei Hu ◽  
Ya Fei Zhang ◽  
Fang Kuo Wang ◽  
Zheng Quan Yan
Keyword(s):  
Standard Deviation ◽  
Aqueous Medium ◽  
Correlation Coefficient ◽  
Relative Standard Deviation ◽  
Near Infrared ◽  
High Selectivity ◽  
Limit Of Detection ◽  
Colorimetric Sensor ◽  
Uv Absorbance ◽  
Relative Standard

A novel near-infrared absorbing colorimetric sensor with multifunctional groups, bis-dibenzo-18-crown-6 squaraine (BCSQ), has been identified and applied for accurate Hg2+analysis based on the decrement of its UV absorbance (A) in the aqueous medium. The proposed method was successfully applied to analyse synthetic Hg2+samples and natural Hg2+samples. The results show that the linear range of Hg2+detection in aqueous medium is 7.5~150×108mol·L1with a correlation coefficient (R) of 0.9983 and a limit of detection (3σ, n=20) of 5.6 ×109mol·L1. The relative standard deviation (R.S.D.) for Hg2+detection was lower than 2.4% (n=5). The proposed method possesses the advantages of simplicity, rapidity, high selectivity and sensitivity.

scholarly journals Validation of a high-performance liquid chromatographic method with fluorecence detection for the quantification of flurbiprofen in tablets

2018 ◽  
Vol 34 (2) ◽  
Author(s):  
Thi Thanh Binh Nguyen ◽  
Anh Mai Tran ◽  
Thuan Hai Duong ◽  
Tung Huu Nguyen ◽  
Tung Thanh Bui
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
High Performance ◽  
Chromatographic Method ◽  
Limit Of Detection ◽  
High Performance Liquid Chromatographic ◽  
Intermediate Precision ◽  
Liquid Chromatographic Method ◽  
Relative Standard ◽  
Liquid Chromatographic

In this study, a high-performance liquid chromatographic method with fluorecence detection was developed for the quantification of flurbiprofen in tablets. A C8 reverse phase column (5 μm, 120 Å, 4.6×150 mm) was used with a mobile phase of acetonitrile : water : glacial acetic acid (65 : 32.5 : 2.5, v/v/v) . The flow rate was 1 ml/min and the column effluent was monitored within 8 minutes. The excitation and emission wavelength were respectively 247 nm and 312 nm. The temperature of flow cell was set at 45˚C and detector sensitivity was 5. The retention time of flurbiprofen was found to be 3.78 minutes. The method was validated under the concentration range of 5 - 100 ng/ml with a tight linear correlation between peak area and sample concentration (R = 0.9999). The proposed method was found to be specific to flurbiprofen, accurate and precise. The percentage recovery was ≤ 100 ± 2%, the relative standard deviation of the repeatability was ≤ 2.08% and the relative standard deviation of the intermediate precision was ≤ 2.96%. The limit of detection and limite of quantification were respectively 0.010 and 0.025 ng/ml.

Study on the Kinetic Spectrophotometric Determination of Selenium (IV) on Oxidation of Neutral Red with Potassium Periodate and its Application

2012 ◽  
Vol 610-613 ◽  
pp. 446-451
Author(s):  
Zhi Rong Zhou ◽  
Li Zhen Zhang
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Fixed Time ◽  
Neutral Red ◽  
Optimum Conditions ◽  
Hair Samples ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

Based on the oxidation of neutral red by KIO4 in 3.2×10-4 mol/L sulfuric acid solution, a simple kinetic spectrophotometric method was developed for the determination of trace amounts of Se(IV).The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of neutral red at 530 nm with a fixed-time method. The decrease in the absorbance of neutral red is proportional to the concentration of Se(IV) in the range 0.0–8.0 µg/L with a fixed time of 4–6 min from the initiation of the reaction. The limit of detection is 0.36 µg/L Se(IV). The influence of the factors such as acidity, concentration of reactants, reaction time, temperature and co-existing ions on the reaction is discussed. The optimum conditions of reaction are established and some kinetic parameters are determined. The apparent activation energy of catalytic reaction is 81.60 kJ/mol. The relative standard deviation for the determination of 0.1 and 0.2 µg/mL Se(IV) was 2.1 and 1.9 %, respectively. The method has been successfully applied to the determination of Se (IV) in tea and human hair samples with the relative standard deviation of 0.33 %–1.5 % and the recovery of 97.5 %–103.5 %.

Kinetic Spectrophotometric Determination of Selenium (IV) by its Catalytic Effect on the Oxidation of Acid Chrome Blue K by Hydrogen Peroxide

2012 ◽  
Vol 538-541 ◽  
pp. 2358-2363 ◽  
Author(s):  
Zhi Rong Zhou ◽  
Li Zhen Zhang
Keyword(s):  
Hydrogen Peroxide ◽  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Fixed Time ◽  
Relative Standard ◽  
Kinetic Spectrophotometric ◽  
Acid Chrome Blue K ◽  
Good Agreement

Based on the oxidation of acid chrome blue K (ACBK) by hydrogen peroxide in 0.002 mol/L sulfuric acid solution, while 1,10-phenanthroline (phen) acts as an activator, a simple kinetic spectrophotometric method was developed for the determination of trace amounts of Se(IV).The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of ACBK at 524 nm with a fixed-time method. The decrease in the absorbance of ACBK is proportional to the concentration of Se (IV) in the range 0.06–1.0 µg/L with a fixed time of 4–10 min from the initiation of the reaction. The limit of detection is 0.018 µg/L Se (IV). The influence of the factors such as acidity, concentration of reactants, reaction time, temperature and co-existing ions on the reaction is discussed. The optimum conditions of reaction are established and some kinetic parameters are determined. The apparent activation energy of catalytic reaction is 62.30 kJ/mol. The relative standard deviation for 11 replicate determination of 0.01 and 0.02 µg/25mL selenium (III) was calculated to be 2.3 % and 2.0 %, respectively. Combined with sulphydryl dextrane gel (SDG) separation and enriching, the method has been successfully applied to the determination of Se (IV) in foodstuff samples with the relative standard deviation of 1.1 %–3.7 % and the recovery of 99.0 %–104.0 %, the results are in good agreement with those provided by HG-AAS method.

scholarly journals Liquid Chromatographic Method with Immunoaffinity Column Cleanup for Determination of Ochratoxin A in Barley: Collaborative Study

2000 ◽  
Vol 83 (6) ◽  
pp. 1377-1383 ◽  
Author(s):  
A Catherine Entwisle ◽  
Alison C Williams ◽  
Peter J Mann ◽  
Philip T Slack ◽  
John Gilbert
Keyword(s):  
Standard Deviation ◽  
Ochratoxin A ◽  
Relative Standard Deviation ◽  
Limit Of Detection ◽  
Collaborative Study ◽  
Immunoaffinity Column ◽  
Low Level ◽  
Relative Standard ◽  
Liquid Chromatographic

Abstract A collaborative study was conducted to evaluate a liquid chromatographic (LC) method with immunoaffinity column cleanup for determination of ochratoxin A. The method was tested at 3 concentration levels of ochratoxin A in barley, which represent possible future European regulatory limits. The test portion was extracted with acetonitrile–water by blending at high speed. The extract was filtered, diluted with phosphate-buffered saline (PBS), and applied to an ochratoxin A immunoaffinity column. The column was washed with water and the ochratoxin A eluted with methanol. The solvent was then evaporated and the residue redissolved in injection solvent. After injection of this solution onto reversed-phase LC column, ochratoxin A was measured by fluorescence detection. Eight samples of low level naturally contaminated barley and 2 samples of blank barley (ochratoxin A not found at the limit of detection of 0.2 μg/kg at the signal-to-noise ratio of 3 to 1) were sent, along with ampules of ochratoxin A, calibrant, and spiking solutions, to 15 laboratories in 13 different European countries. Test portions were spiked with ochratoxin A at levels of 4 ng/g, and recoveries ranged from 65 to 113%. Based on results for spiked samples (blind duplicates) and naturally contaminated samples (blind duplicates at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 4 to 24%, and the relative standard deviation for reproducibility (RSDR) ranged from 12 to 33%. The method showed acceptable within- and between-laboratory precision, as evidenced by HORRAT values, at the low level of determination for ochratoxin A in barley.

Rapid determination of fosetyl-aluminium in commercial pesticide formulations by high-performance liquid chromatography

2014 ◽  
Vol 68 (6) ◽  
Author(s):  
Helen Karasali ◽  
Konstantinos Kasiotis ◽  
Kyriaki Machera
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
High Performance ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
Hplc Method ◽  
Negative Ion ◽  
Rp Hplc ◽  
Relative Standard

AbstractAn isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC) method with diode array detection (DAD) was developed for the determination of aluminium tris(ethyl phosphonate) (fosetyl-aluminium, fosetyl-Al) in plant-protection products. The method involves extraction of the active ingredient by sonication of the sample with water and direct measurement by RPHPLC. The isocratic RP-HPLC method for the analysis of fosetyl-Al thus developed was then validated for specificity, linearity, precision, and accuracy. The chromatographic peak confirmation was performed by LC-MS using electron spray ionisation in the negative-ion mode. The repeatability of the method, expressed as relative standard deviation (RSD, %), was found to be 0.5 % and the limit of detection was 0.035 mg mL−1. The average recoveries of the three fortification levels varied from 96.7 % to 100.6 % and the RSDs ranged between 2.6 % and 6.3 %. The precision of the method was also considered to be acceptable as the experimental repeatability relative standard deviation (RSDr) was lower than the RSDr, calculated using the Horwitz equation. The method is rapid, simple, accurate, cost-effective, and provides a new and reliable means for the analysis of fosetyl-Al in formulated products.

scholarly journals Spectrophotometic Determination of Caffeine and Vitamin B6 in Selected Beverages, Energy/Soft Drinks and Herbal Products

2021 ◽  
Vol 28 (1) ◽  
pp. 22-29
Author(s):  
A.L. Ogunneye ◽  
O.O. Banjoko ◽  
M.R. Gbadamosi ◽  
O.H. Falegbe ◽  
K.H. Moberuagba ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Vitamin B6 ◽  
Limit Of Detection ◽  
Soft Drinks ◽  
Sensitivity Limit ◽  
Limit Of Quantification ◽  
Herbal Products ◽  
Relative Standard

In this study, a simple, sensitive and reproducible spectrophotometric technique has been developed and validated for the determination of caffeine and vitamin B6 in beverages, energy/soft drinks and herbal products. The determination of caffeine and vitamin B6 in the respective samples were carried out at maximum (λmax) absorbance of 272 and 290 nm respectively. The method was validated in terms of linearity, sensitivity (limit of Detection (LOD) and limit of Quantification (LOQ), accuracy (% Recovery), precision (relative standard deviation). The method was linear from (4-20 µg/ml and 50 - 250 µg/ml with r 2 of 0.9991 and 0.9996 for vitamin B6 and caffeine respectively. The accuracy of the method ranged from 99.48 - 101.42% for caffeine and 99.94% - 102.35% for vitamin B6. The detection limit and quantification limit were 0.192 µg/ml and 0.640 µg/ml for vitamin B6 while 0.0155 µg/ml and 0.0518 µg/ml was obtained for caffeine. The method for the two analytes was found to be precise as the percentage relative standard deviation was below 5%. Therefore, the method proposed in this study is rapid, suitable and can be used as a quality control index for caffeine and vitamin B6 in beverages, energy/soft drinks and herbal products in industries. Keywords: Caffeine, Vitamin B6, Beverages, Energy/Soft drinks, Herbal products, Spectrophotometry

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