scholarly journals Factors affecting the detection limit of a flow- injection spectrophotometric procedure

1988 ◽  
Vol 214 ◽  
pp. 447-453 ◽  
Author(s):  
Julian F. Tyson ◽  
Andrew B. Marsden
2018 ◽  
Vol 33 (2) ◽  
pp. 47
Author(s):  
Orlando Fatibello-Filho ◽  
Heberth Juliano Vieira

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.


2010 ◽  
Vol 10 (2) ◽  
pp. 167-171 ◽  
Author(s):  
Hermin Sulistyarti ◽  
Spas D. Kolev ◽  
Stephanie Lim

The importance of developing method for thiocyanate becomes obvious, because thiocyanate can inhibit iodine uptake of thyroid gland leading to mumps disease. In this work, thiocyanate is oxidized by permanganate in the acid donor stream to cyanide, which is directly converted to hydrogen cyanide. Then, hydrogen cyanide diffuses through a Teflon membrane into acceptor stream containing nickel(II) in ammoniacal buffer to form tetracyanonickelate(II) which is detected spectrophotometrically at 267 nm. Analytical figures of merit were linear up to 50 mg L-1 for thiocyanate, with RSD of 1.34%, and detection limit of 0.07 mg L-1, respectively. Interfering anions were eliminated under stoichiometric amount of permanganate and sample throughput was 20 h-1. The method was validated for determining thiocyanate samples from synthetic and gold process waters with satisfactory results.   Keywords: Thiocyanate, flow injection, permanganate, spectrophotometry


2001 ◽  
Vol 84 (1) ◽  
pp. 59-64 ◽  
Author(s):  
Inês P A Morais ◽  
António O S S Rangel ◽  
M Renata S Souto

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.


1990 ◽  
Vol 36 (4) ◽  
pp. 662-665 ◽  
Author(s):  
E P Gil ◽  
H T Tang ◽  
H B Halsall ◽  
W R Heineman ◽  
A S Misiego

Abstract A competitive enzyme-linked immunoabsorbent assay based on the flow-injection amperometric detection of p-aminophenol has been investigated with use of the materials and general procedure of a commercial kit for the determination of theophylline in human serum. The antibody is immobilized on glass beads, and the enzyme label is alkaline phosphatase (EC 3.1.3.1). The high currents generated during the electrochemical detection allowed a rapid (35 min) and simple determination of theophylline throughout its therapeutic range (10-20 mg/L) and also in the subtherapeutic range (detection limit of about 80 micrograms/L).


1989 ◽  
Vol 11 (2) ◽  
pp. 87-88 ◽  
Author(s):  
Sveinbjörn Gizurarson

The applicability of a single-channel flow-injection system with immobilized enzyme coil (Technicon) and UV detection to the determination of glucose is described. The method was used for a pure glucose solution and for serum. The detection limit was 0.10 mM, the rate of determination was 20-40 per hour and the precision was satisfactory. The system is very simple and practical when many analysis are to be determined periodically.


2013 ◽  
Vol 11 (2) ◽  
pp. 320-323 ◽  
Author(s):  
Dimitrios Nikolelis ◽  
Nikolas Psaroudakis ◽  
Antonis Michaloliakos ◽  
Georgia-Paraskevi Nikoleli ◽  
Michael Scoullos

AbstractAn electrochemical biosensor based on a supported polymerized lipid film with incorporated sheep anti-3,3′,4,4′ tetrachlorobiphenyl (PCB congener 77) antibody using flow injection analysis was developed. The polymerized lipid film contained 85% (w/w) dipalmitoylphosphatidylcholine (DPPC) and 15% (w/w) dipalmitoylphosphatidic acid (DPPA), methacrylic acid, ethylene glycol dimethacrylate, AIBN and sheep anti-congener 77 antiserum. Congener 77 was injected into flowing carrier electrolyte and the flow stopped to detect the antigen. These membranes gave only a single transient proportional to log [congener 77] from 10−8 to 10−5 M, with a detection limit of ca. 10−8 M. A membrane containing 35% (w/w) DPPA was used to examine regeneration. The maximum number of cycles was about 5.


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