scholarly journals A Novel and Sensitive Method for the Determination of VitaminB2(Riboflavin) in Urine and Pharmaceutical Samples Using an Aqueous Two-Phase Extraction

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Sabah Shiri ◽  
Tahere Khezeli ◽  
Sami Sajjadifar ◽  
Ali Delpisheh ◽  
Moayed Avazpour ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Standard Deviation ◽  
Limit Of Detection ◽  
Vitamin B ◽  
Phase Extraction ◽  
Two Phase ◽  
Pharmaceutical Samples ◽  
Relative Standard ◽  
Aqueous Two Phase Extraction

A novel, simple, and more sensitive spectrophotometric procedure has been developed for the determination of vitamin B2(riboflavin) by an aqueous two-phase extraction (ATPE). An ATPE is formed mostly by water and does not require an organic solvent. Other ATPE components used in this study were the polymer, polyethylene glycol (PEG), and some salts such as Na2SO4and Na2CO3. The method is based on the interaction between vitamin B2(riboflavin) and sodium sulfate (Na2SO4) in an acidic medium (pH 6.4). The influences of effective parameters such as salt (type and concentration), polyethylene glycol (molecular weight and concentration), temperature, centrifuging time, and pH of the sample solution were studied and optimized. The linear range was 1.3–320 ng/mL (R2=0.9991;n=10) with the relative standard deviation (RSD) for 60 ng/mL 3.68%. The limit of detection (LOD) calculated from three times of standard deviation of blank were 0.2 ng/mL and recoveries from analysis of real samples between 94.82% and 103.98% were obtained for the determination of vitamin B2(riboflavin) in urine and pharmaceutical samples.

scholarly journals Spectrophotometric Determination of Iron(II) after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nahid Pourreza ◽  
Saadat Rastegarzadeh ◽  
Ali Reza Kiasat ◽  
Hossein Yahyavi
Keyword(s):  
Polyethylene Glycol ◽  
Solid Phase Extraction ◽  
Silica Gel ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Calibration Graph ◽  
Phase Extraction ◽  
Relative Standard

A new solid phase extraction procedure was developed for preconcentration of iron(II) using silica gel-polyethylene glycol (silica-PEG) as an adsorbent. The method is based on retention of iron(II) as 2,2′ bipyridine complex on silica-PEG. The retained complex is eluted by 1.0 mol L−1of sulfuric acid-acetone mixture (1:2) and its absorbance is measured at 518 nm, spectrophotometrically. The effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. The calibration graph was linear in the range of 1–60 ng mL−1of iron(II). The limit of detection based on3Sbwas 0.57 ng mL−1and relative standard deviations (R.S.D) for ten replicate measurements of 12 and 42 ng mL−1of iron(II) were 2.4 and 1.7%, respectively. The method was applied to the determination of of iron(II) in water, multivitamin tablet, and spinach samples.

scholarly journals Aqueous Two-Phase Systems: A New Approach for the Determination of Brilliant Blue FCF in Water and Food Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Sabah Shiri ◽  
Tahere Khezeli ◽  
Shahram Lotfi ◽  
Sina Shiri
Keyword(s):  
Polyethylene Glycol ◽  
Standard Deviation ◽  
Food Samples ◽  
Brilliant Blue ◽  
Phase System ◽  
Optimum Conditions ◽  
Two Phase ◽  
Brilliant Blue Fcf ◽  
Relative Standard

A novel, simple, and more sensitive spectrophotometric procedure has been developed for the determination of brilliant blue FCF in water and food samples by an aqueous two-phase system (ATPS). In this method, adequate amount of polyethylene glycol/ sodium carbonate (PEG-4000/Na2CO3) was added to aqueous solution for formation of a homogeneous solution. To the mixture solution, suitable amount ofNa2CO3was added, the mixture solution was shaken until the salt was dissolved, and then it was separated into two clear phases easily and rapidly. The target analyte in the water sample was extracted into the polyethylene glycol phase. After extraction, measuring the absorbance at 634 nm was done. The effects of different parameters such as polyethylene glycol (type and concentration), pH, salt (type and amount), centrifuge time, and temperature on the ATPS of dye was investigated and optimum conditions were established. Linear calibration curves were obtained in the range of 0.25–750 ng/mL for brilliant blue FCF under optimum conditions. Detection limit based on three times the standard deviation of the blank (3Sb) was 0.12 ng/mL. The relative standard deviation (RSD) for 400 ng/mL was 3.14%. The method was successfully applied to the determination of brilliant blue FCF in spiked samples with satisfactory results. The relative recovery was between 96.0 and 102.2%.

scholarly journals Determination of Sodium Cromoglycate by a New Kinetic Spectrophotometric Method in Biological Samples

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Mohsen Keyvanfard ◽  
Khadijeh Alizad ◽  
Razieh Shakeri
Keyword(s):  
Standard Deviation ◽  
Sodium Cromoglycate ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Biological Samples ◽  
Limit Of Detection ◽  
Micellar Medium ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A new kinetic spectrophotometric method is described for the determination of ultratrace amounts of sodium cromoglycate (SCG). The method based on catalytic action of SCG on the oxidation of amaranth with periodate in acidic and micellar medium. The reaction was monitored spectrophotometrically by measuring the decrease in absorbance of the amaranth at 518 nm, for the first 4 min from initiation of the reaction. Calibration curve was linear in the range of 4.0−36.0 ng mL−1SCG. The limit of detection is 2.7 ng mL−1SCG. The relative standard deviation (RSD) for ten replicate analyses of 12, 20, and 28 ng mL−1SCG was 0.40%, 0.32%, and 0.53%, respectively. The proposed method was used for the determination of SCG in biological samples.

Permanganate Based Chemiluminescence Analysis of Cefoperazon

2013 ◽  
Vol 333-335 ◽  
pp. 1807-1810
Author(s):  
De Yi Zhang ◽  
Li Wen Zheng
Keyword(s):  
Excited State ◽  
Standard Deviation ◽  
Potassium Permanganate ◽  
Injection Technique ◽  
Pharmaceutical Samples ◽  
Analysis Process ◽  
Relative Standard ◽  
Novel Method ◽  
Emitting Species

In this paper, a novel method fog determination of chemiluminescence (CL) spectra utilizing LS55 luminescence spectrophotometer was proposed. By this means, the CL spectra generated from the oxidation of cephalosporins with potassium permanganate was investigated. The result indicated that acid potassium permanganate CL system has more then three emitting species, excited state Mn(Ⅱ), Mn(Ⅲ) and singlet oxygen all could be assigned as the possible emitting species of this CL system. Base on above investigation results, sodium cefoperazone in pharmaceutical samples was determined by a CL analysis process combining with flow-injection technique. The detection limits estimated by a conservative model (3σ) of cefoperazone was 0.1µg dm-3, and the maximum relative standard deviation (RSD) was not more than 0.8 % (n=11, ρ=20µg dm-3).

Aqueous Two-Phase Extraction of Potassium Glycyrrhizinate with Polyethylene Glycol/(NH4)2SO4

2012 ◽  
Vol 550-553 ◽  
pp. 1687-1690
Author(s):  
Chen Sun ◽  
Wen Ju Liu ◽  
Hai Ming Zhang
Keyword(s):  
Polyethylene Glycol ◽  
Mass Fraction ◽  
Ph Value ◽  
Phase System ◽  
Phase Extraction ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Result Show ◽  
A New Technique ◽  
Aqueous Two Phase Extraction

An aqueous two-phase system of polyethylene glycol (PEG)/(NH4)2SO4 with the behavior of forming aqueous two-phase and the distribution rules of potassium glycyrrhizinate in the aqueous two-phase system were studied. Effects of the molecular weight of PEG, the mass fraction of PEG and (NH4)2SO4, and pH value were investigated. The result show that when the mass fraction of PEG1000 was 50%, the mass fraction of (NH4)2SO4 was 5.7%, and pH value was 6.5, the highest extraction recovery of potassium glycyrrhizinate could reach 99.7%. This aqueous two-phase extraction may provide a new technique for separation of potassium glycyrrhizinate.

scholarly journals Determination of Niacin in Infant Formula by Solid-Phase Extraction/Liquid Chromatography: Peer-Verified Method Performance–Interlaboratory Validation

2002 ◽  
Vol 85 (3) ◽  
pp. 654-664 ◽  
Author(s):  
Denis E LaCroix ◽  
Wayne R Wolf ◽  
G William Chase
Keyword(s):  
Liquid Chromatography ◽  
Standard Deviation ◽  
Reference Material ◽  
Infant Formula ◽  
Solid Phase ◽  
Phase Extraction ◽  
Relative Standard ◽  
Interlaboratory Validation ◽  
Extraction Liquid

Abstract This paper reports the results of the interlaboratory peer validation study of AOAC Peer-Verified Method (PVM) 1:2000 for the determination of niacin in infant formula by solid-phase extraction/liquid chromatography. We have used a Data Quality Objectives (DQO) approach to address not only method variability and robustness but also accuracy of data through the use of an appropriate reference material in conjunction with the interlaboratory validation study. Our DQO included the following: (1) statistical agreement of analytical results and quantitative recovery between 2 collaborating laboratories; (2) the repeatability relative standard deviation (RSDr) values and the HORRAT (Horwitz ratio) obtained (1.07), which satisfied the criteria of the Horwitz “limits of acceptability” at the analyte level present; (3) validation of lack of interference; and (4) accuracy agreement within assigned values for a certified reference material. National Institute of Standards and Technology Standard Reference Material (NIST SRM) 1846 Infant Formula, with a certified value of 63.3 ± 7.6 μg/g for niacin content, was used as a test material for collaborative study and accuracy assessment. Niacin values obtained by the originating laboratory were 59.7 ± 4.0 μg/g (95% confidence interval [CI] = 1.4 μg/g with a relative standard deviation [RSD] of 6.7%) and by the peer laboratory were 56.6 ± 6.6 μg/g (95% CI = 4.1 μg/g, with an RSD of 11.7%). Statistical evaluation using the means equivalence test showed that nicotinic acid values obtained by the peer laboratory were equivalent to those values obtained by the originating laboratory. Linear calibration curves and quantitative recovery were obtained. Integration of the PVM process with a readily available certified reference material gives the user confidence in the accuracy of the data generated by the method through traceability to the reference material used.

Kinetic Spectrophotometric Determination of Ruthenium by its Catalytic Effect on the Reduction of Spadns with Sodium Hypophosphite in Micellar Media

2012 ◽  
Vol 204-208 ◽  
pp. 4067-4070 ◽  
Author(s):  
Zhi Rong Zhou ◽  
Li Zhen Zhang
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Catalytic Effect ◽  
Limit Of Detection ◽  
Fixed Time ◽  
Sodium Hypophosphite ◽  
Micellar Media ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A simple kinetic spectrophotometric method was developed for the determination of trace amounts of Ru (III). The method is based on the reduction of spadns by sodium hypophosphite (NaH2PO2) in micellar media. The reaction was monitored spectrophotometrically by measuring the decrease in the absorbance of spadns at 515 nm with a fixed-time method. The decrease in the absorbance of spadns is proportional to the concentration of Ru (III) in the range 0.40–10.0 μg/L with a fixed time of 2.5–7.0 min from the initiation of the reaction. The limit of detection is 0.12 μg/L Ru (III). The relative standard deviation for the determination of 0.10 and 0.20 μg/25mL Ru (III) was 2.3 % and 2.0 %, respectively. The method was applied to the determination of Ru (III) in some ores and metallurgy products.

scholarly journals Flotation-Spectrophotometric Method for the Determination of Aluminium ion Using Xylenol Orange

2011 ◽  
Vol 8 (4) ◽  
pp. 1528-1535 ◽  
Author(s):  
F. Nekouei ◽  
Sh. Nekouei
Keyword(s):  
Standard Deviation ◽  
Spectrophotometric Method ◽  
Calibration Curve ◽  
Limit Of Detection ◽  
Xylenol Orange ◽  
Molar Absorptivity ◽  
Relative Standard ◽  
Ion Associate ◽  
Sensitive Method

A simple, fast, reproducible and sensitive method for the flotation- spectrophotometric determination of Al3+is reported. The apparent molar absorptivity (ε) of the ion associate was determined to be 8.35×104L mol-1cm-1. The calibration curve was linear in the concentration range of 1.0-50 ng mL-1of Al3+with a correlation coefficient of 0.9997. The limit of detection (LOD) was 0.621 ng mL. The relative standard deviation (RSD) at 10 and 30 ng mL-1of aluminium were 1.580 and 2.410% (n=7) respectively. The method was applied for measuring the amount of aluminium in water samples.

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.

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