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 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 Solidified Floating Organic Drop Microextraction for the Detection of Trace Amount of Lead in Various Samples by Electrothermal Atomic Absorption Spectrometry

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Oya Aydın Urucu ◽  
Şeyda Dönmez ◽  
Ece Kök Yetimoğlu
Keyword(s):  
Standard Deviation ◽  
Electrothermal Atomic Absorption Spectrometry ◽  
Chelating Agent ◽  
Absorption Spectrometry ◽  
Food Samples ◽  
Lead Ion ◽  
Optimum Conditions ◽  
Relative Standard ◽  
Novel Method

A novel method was developed for determination of trace amounts of lead in water and food samples. Solidified floating organic drop microextraction was used to preconcentrate the lead ion. After the analyte was complexed with 1-(2-pyridylazo)-2-naphthol, undecanol and acetonitrile were added as extraction and dispersive solvent, respectively. Variables such as pH, volumes of extraction and dispersive solvents, and concentration of chelating agent were optimized. Under the optimum conditions, the detection limit of Pb (II) was determined as 0.042 µg L−1 with an enrichment factor of 300. The relative standard deviation is <10%. Accuracy of the developed procedure was evaluated by the analysis of certified reference material of human hair (NCS DC 73347) and wastewater (SPS-WW2) with satisfactory results. The developed procedure was then successfully applied to biscuit and water samples for detection of Pb (II) ions.

Optimization of an Aqueous Two-Phase System for the Determination of Trace Ethyl Carbamate in Red Wine

2019 ◽  
Vol 82 (8) ◽  
pp. 1377-1383 ◽  
Author(s):  
LIJUAN MA ◽  
WENZHE TONG ◽  
LIPING DU ◽  
SHIYONG HUANG ◽  
JINYAN WEI ◽  
...  
Keyword(s):  
Quantitative Determination ◽  
Red Wine ◽  
Ethyl Carbamate ◽  
Phase System ◽  
Extraction Temperature ◽  
Two Phase ◽  
Aqueous Two Phase System ◽  
Relative Standard ◽  
Standard Deviations

ABSTRACT In this study, a novel method using gas chromatography–mass spectrometry coupled with ethanol and K2HPO4 aqueous two-phase system (ATPS) was established for the quantitative determination of trace ethyl carbamate (EC) in red wine. The parameters that influence EC extraction in an aqueous two-phase system, including extraction temperature, time, pH, and ethanol concentration, were optimized. Method validation results indicated that the regression coefficient of the proposed method was 0.9979 in the linear range of 10 to 100 μg/L, and the limits of detection and quantification were 2.8 and 9.2 μg/L, respectively. Four red wine samples made from different grape varieties were processed by the proposed method for the repeatability verification, and EC concentrations were between 15.8 and 37.3 μg/L, with the relative standard deviations ranging from 3.5 to 6.6%. Results of the precision assay showed the average recovery of EC in red wine at 95.4 to 107.1%, with the relative standard deviations ranging from 1.4 to 6.2%. This method proved to be simple and reliable for quantitative determination of trace EC in red wine and would give guidance for quality monitoring of various red wines in the production process.

Fluorometric Determination of Selenium in Foods

1974 ◽  
Vol 57 (2) ◽  
pp. 368-372 ◽  
Author(s):  
Milan Ihnat
Keyword(s):  
Standard Deviation ◽  
Milk Powder ◽  
Skim Milk ◽  
Skim Milk Powder ◽  
Food Samples ◽  
Fluorometric Method ◽  
Fluorometric Determination ◽  
Relative Standard ◽  
The Mean

Abstract A fluorometric method using 2,3-diaminonaphthalene for estimating selenium has been evaluated with regard to its applicability to food samples. Charring of the sample during digestion appeared to result in losses of native and added selenium from some samples, so a modified wet digestion procedure was introduced. Digestion first in nitric acid followed by a mixture of nitric-perchloric-sulfuric acids substantially reduced the incidence of sample charring for a variety of foods. The mean apparent recovery of selenium added as selenite or selenate at 100 and 500 ng levels to 0.1 and 1.0 g corn cereal, skim milk powder, and meat and 0.1 g fish was 101.0%; the actual recovery of the same levels of selenium from standard solutions was 96.6%. For a variety of samples containing 5—750 ng native or added selenium, the standard deviation as 4.7 + 1.95 X 10-2W ng, where W = ng selenium in the sample taken for analysis. The relative standard deviation (RSD) as a function of selenium weight (ng) was 50% (10), 6.7% (100), 4.3% (200), 3.1% (400), 2.7% (600), and 2.5% (800). The detection limit (weight of selenium at which RSD = 50%) was 10 ng at a mean blank level of 25 ng.

Cloud Point Extraction-Fluorimetric Combined Methodology for the Determination of Magnolol

2013 ◽  
Vol 699 ◽  
pp. 34-39
Author(s):  
Li Liu ◽  
Xia Shi Zhu
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Cloud Point ◽  
Relative Standard Deviation ◽  
Cloud Point Extraction ◽  
Calibration Graph ◽  
Optimum Conditions ◽  
Relative Standard ◽  
Triton X

A new Triton X-114 cloud point extraction combined with fluorometry method for analysis of magnolol in drug samples was developed. Under the optimum conditions, the calibration graph was linear in the range of 2.0-150.0ng/mL of magnolol in the initial solution with r = 0.9998. Detection limit (DL) was 0.03ng/mL (S/N=3) and the relative standard deviation (RSD) for 20.0ng/mL of magnolol was 2.79%(n=11). The method was successfully applied for the determination of magnolol in drug samples with satisfactory results.

Iodometric determination of 2-mercaptobenzthiazole by coulometric titration

1982 ◽  
Vol 47 (2) ◽  
pp. 588-593 ◽  
Author(s):  
Zdeněk Kučera ◽  
Milan Karlík ◽  
Jiří Krofta
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Coulometric Titration ◽  
Optimum Conditions ◽  
End Point ◽  
Relative Standard ◽  
Standard Deviations

The optimum conditions were found for the determination of 2-mercaptobenzthiazole (MBT) by coulometric titration with the generated iodine using biamperometric indication of the titration end point. Use is made of the oxidation to the disulphide (n = 1) and to benzothiazole-2-sulphinate (n = 4) in the regions pH 4.5-8.5 and 10-12, respectively. Eight repeated titrations to the disulphide gave the relative standard deviations 0.27% and 1.23% in the determination of 1 675 and 33.5 μg MBT, respectively, seven repeated titrations of 419 μg MBT to benzothiazole-2-sulphinate afforded results with the relative standard deviation 0.34%.

scholarly journals Determination of Methylcellulose and Hydroxypropyl Methylcellulose Food Gums in Food and Food Products: Collaborative Study

2007 ◽  
Vol 90 (3) ◽  
pp. 786-793 ◽  
Author(s):  
Robert G Harfmann ◽  
Balasaheb K Deshmukh ◽  
Jerry Conklin ◽  
Maciej Turowski ◽  
Stephanie Lynch ◽  
...  
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Hydroxypropyl Methylcellulose ◽  
Collaborative Study ◽  
Food Samples ◽  
Size Exclusion ◽  
Official Method ◽  
Relative Standard ◽  
Aoac Official

Abstract A collaborative study was performed to determine the reproducibility of a method for the determination of methylcellulose (MC) and hydroxypropyl methylcellulose (HPMC) in food. These widely used food gums possess unusual solubility characteristics and cannot accurately be determined by existing dietary fiber methods. The new method uses the enzyme-digestion procedure of AOAC Official Method 991.43. Digestate solutions must be refrigerated to fully hydrate MC or HPMC. The chilled solutions are filtered and analyzed by size-exclusion liquid chromatography. Collaborating laboratories received 28 samples containing MC or HPMC in the range of 0100%. The sample set included blind duplicates of 5 food matrixes (bread, milk, fish, potato, and powdered juice drink). Cochran and Grubbs tests were used to eliminate outliers. For food samples containing MC, values for within-laboratory precision, repeatability relative standard deviation (RSDr), ranged from 4.2 to 16%, and values for among-laboratories precision, reproducibility relative standard deviation (RSDR), ranged from 11 to 20%. For HPMC samples, RSDr values ranged from 6.4 to 27%, and RSDR values ranged from 17 to 39%. Recoveries of MC and HPMC from the food matrixes ranged from 78 to 101%. These results show acceptable precision and reproducibility for the determination of MC and HPMC, for which no Official AOAC Methods exist. It is recommended that this method be adopted as AOAC Official First Action.

Spctrophotometric Determination of Trace Ruthenium by its Catalytic Effect on Oxidation of 3,5-DiBr-PADAP with KIO4

2012 ◽  
Vol 554-556 ◽  
pp. 1999-2005
Author(s):  
Zhi Rong Zhou ◽  
Qun Wang ◽  
Shu Yuan Zhang
Keyword(s):  
Activation Energy ◽  
Standard Deviation ◽  
Detection Limit ◽  
Catalytic Reaction ◽  
Oxidation Reaction ◽  
Catalytic Effect ◽  
Optimum Conditions ◽  
Potassium Periodate ◽  
Relative Standard

A spectrophotometric method for the determination of ruthenium (III) is described, based on its catalytic effect on the oxidation reaction of 2-[(3,5-dibromo-2-pyridy)azo]-5-diethylaminophenol (3,5-diBr-PADAP) with potassium periodate in 0.008 mol/L sodium hydroxide medium and in the presence of OP emulsifier (p-iso-octyl phenoxy polyethoxy ethanol) at 100 °C. The above reaction is followed spectrophotometrically by measuring the decrease in the absorbance at 530 nm for the catalytic reaction of 3,5-diBr-PADAP. The calibration curve for the recommended method was linear in the concentration range over 0.04 µg/L–1.0 µg/L and the detection limit of the method for Ru (III) is 0.012 µg/L. 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 100.48 kJ/mol. The relative standard deviation for the determination of ruthenium (III) at the concentration of 0.02 µg/25mL is calculated to be 2.30 % (n=11). In combination with distilled separation, the method has been successfully applied for the determination of trace ruthenium (III) in some ores and metallurgy products with the relative standard deviations (RSD) over 1.8 %–2.9 % and the recovery over 98.1 %–103.1 %.

Determination of Trace Chromium (VI) in Tanning Wastewater by Flow Injection Spectrophotometry

2010 ◽  
Vol 113-116 ◽  
pp. 1732-1734
Author(s):  
Xin Zhao ◽  
Zhi Hui Sui ◽  
Jing Bin Zhang
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Flow Injection ◽  
Spectrophotometric Method ◽  
H2so4 Solution ◽  
Optimum Conditions ◽  
Chromium Vi ◽  
Relative Standard ◽  
Simple Flow

In 1.0 mol/L H2SO4 solution, a rapid and simple flow—injection spectrophotometric method has been developed for Cr(Ⅵ) determination, based on the violet—red Cr(Ⅵ)—diphenylcarbazide chelates formed by reactions. The results show, under optimum conditions, the maximum absorption of the complex is at 540 nm and the detection limits of the method is 0.0136mg/L for Cr(Ⅵ) and Beer’s law is obeyed for Cr(Ⅵ) in the range of 0.03—1.60mg/L. The determination frequency is l00 times/h. The relative standard deviation of eleven replicates is less than 4.0%. The method has been applied to the determination of trace Cr(Ⅵ) in tanning wastewater with satisfactory results.

Green effervescence assisted dispersive liquid–liquid microextraction based on a hydrophobic deep eutectic solvent for determination of Sunset Yellow and Brilliant Blue FCF in food samples

2018 ◽  
Vol 42 (18) ◽  
pp. 14901-14908 ◽  
Author(s):  
Mahboobeh Ghorbani Ravandi ◽  
Mohammad Reza Fat’hi
Keyword(s):  
Deep Eutectic Solvent ◽  
Food Samples ◽  
Brilliant Blue ◽  
Synthetic Dyes ◽  
Sunset Yellow ◽  
Brilliant Blue Fcf ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction ◽  
Sensitive Method

In this study, a simple, fast and sensitive method called effervescence assisted dispersive liquid–liquid microextraction based on a hydrophobic deep eutectic solvent (EADLLME-DES) was used to extract synthetic dyes from food samples.

Sign in / Sign up

Export Citation Format

Share Document