Gas Diffusion-Flow Injection Determination of Free and Total Sulfur Dioxide in Wines by Conductometry

1998 ◽  
Vol 63 (6) ◽  
pp. 770-782 ◽  
Author(s):  
Petr Kubáň ◽  
Pavel Janoš ◽  
Vlastimil Kubáň
Keyword(s):  
Sulfuric Acid ◽  
Detection Limit ◽  
Sulfur Dioxide ◽  
Flow Injection ◽  
Gas Diffusion ◽  
Total Sulfur ◽  
Diffusion Flow ◽  
Pvdf Membrane ◽  
Relative Standard

Sensitive flow injection analysis methods for the determination of free and total sulfur dioxide in wines are presented. The bound S(IV) was liberated by alkaline hydrolysis with 4 mol/l NaOH. All forms of S(IV) were liberated from the sample zone by sulfuric acid and subsequently transported through a microporous PVDF membrane. The penetrated gases were collected in water for preselected period and determined by conductometry with detection limit 1 mg/l and relative standard deviations 0.8 and 0.6% at 10 and 150 mg/l (n = 10) for free and total S(IV), respectively. The results are comparable with those obtained by standard titrimetric procedures with visual (Czech State Standard) and/or potentiometric indication.

scholarly journals Spectrophotometric flow injection procedure to indirect determination of paracetamol in pharmaceutical formulations using o-tolidine as reagent

2018 ◽  
Vol 33 (2) ◽  
pp. 47
Author(s):  
Orlando Fatibello-Filho ◽  
Heberth Juliano Vieira
Keyword(s):  
Standard Deviation ◽  
Detection Limit ◽  
Flow Injection ◽  
Pharmaceutical Formulations ◽  
Injection Method ◽  
Indirect Determination ◽  
Analytical Curve ◽  
Relative Standard ◽  
Injection Procedure

A spectrophotometric flow injection method for the determination of paracetamol in pharmaceutical formulations is proposed. The procedure was based on the oxidation of paracetamol by sodium hypochloride and the determination of the excess of this oxidant using o-tolidine dichloride as chromogenic reagent at 430 nm. The analytical curve was linear in the paracetamol concentration range from 8.50 x 10-6 to 2.51 x 10-4 mol L-1 with a detection limit of 5.0 x 10-6 mol L-1. The relative standard deviation was smaller than 1.2% for 1.20 x 10-4 mol L-1 paracetamol solution (n = 10). The results obtained for paracetamol in pharmaceutical formulations using the proposed flow injection method and those obtained using a USP Pharmacopoeia method are in agreement at the 95% confidence level.

scholarly journals Determination of Sulfate in Natural and Residual Waters by Turbidimetric Flow-Injection Analysis

2001 ◽  
Vol 84 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Inês P A Morais ◽  
António O S S Rangel ◽  
M Renata S Souto
Keyword(s):  
Detection Limit ◽  
Flow Injection ◽  
Reference Method ◽  
Previous Treatment ◽  
Barium Chloride ◽  
Sulfate Solution ◽  
Injection System ◽  
Residual Water ◽  
Relative Standard

Abstract A turbidimetric flow-injection system was developed for the determination of sulfate in natural and residual water samples, with no previous treatment, using spectrophotometric detection. The precipitating agent, 7.0% (w/v) barium chloride solution prepared in 0.10% (w/v) polyvinyl alcohol, was added by using the merging-zones approach. A 100 mg/L sulfate solution in 0.07M nitric acid was mixed with the sample before it entered the injection loop to improve the detection limit, provide in-line pH adjustment, and prevent the interference of some anionic species. The relative standard deviations of the results were between 1.4 and 3.0% and were in agreement with results obtained by the reference method. Samples within a linear concentration range of 10–120 mg SO42−/L can be analyzed at a rate of 40/h. The detection limit is 5 mg SO42−/L.

Sensitive and ultra-fast determination of arsenic(III) by gas-diffusion flow injection analysis with chemiluminescence detection

2007 ◽  
Vol 583 (1) ◽  
pp. 72-77 ◽  
Author(s):  
Cristina Lomonte ◽  
Matthew Currell ◽  
Richard J.S. Morrison ◽  
Ian D. McKelvie ◽  
Spas D. Kolev
Keyword(s):  
Flow Injection ◽  
Flow Injection Analysis ◽  
Gas Diffusion ◽  
Chemiluminescence Detection ◽  
Diffusion Flow ◽  
Fast Determination

scholarly journals An Environmentally Friendly Flow Injection-Gas Diffusion System Using Roselle (Hibiscus sabdariffa L.) Extract as Natural Reagent for the Photometric Determination of Sulfite in Wines

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Preeyaporn Reanpang ◽  
Teerarat Pun-uam ◽  
Jaroon Jakmunee ◽  
Supada Khonyoung
Keyword(s):  
Flow Injection ◽  
Environmentally Friendly ◽  
Photometric Determination ◽  
Gas Diffusion ◽  
Hibiscus Sabdariffa ◽  
Permeable Membrane ◽  
Relative Standard ◽  
Color Fading ◽  
Acceptor Solution

In this work, a green and simpler method for photometric determination of sulfite based on a flow injection-gas diffusion (FI-GD) system using a natural reagent extracted from roselle (Hibiscus sabdariffa L.) was proposed. Despite the fact that the employed reaction is not selective to sulfite, its sensitivity is high, and the selectivity can be improved by coupling a GD unit to the FI system. The method involves monitoring a decrease in absorbance of the reagent solution that is used as an acceptor solution. When a standard solution or sample solution was injected into an acidic donor stream, the liberated sulfur dioxide diffuses through a gas-permeable membrane of the GD unit into the acceptor solution, causing color fading of the reagent. A linear analytical curve in the range of 5–100 mg L−1 was obtained with a detection limit of 2 mg·L−1. Relative standard deviations of 0.9%, 0.6%, and 0.6% were obtained for the determination of 30, 70, and 100 mg·L−1 SO32- (n = 11). The developed method was applied to wine samples, giving results that agreed with those obtained with the Ripper titrimetric method. The proposed method offers advantages of simplicity, cost-effectiveness, and being environmentally friendly such as reduced chemical consumption and less waste generation.

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