Spectrophotometric determination of peroxydisulphate with o -dianisidine by flow injection (original) (raw)
Related papers
Journal of Chromatography A, 2010
A new method for the determination of peroxydisulfate using ion chromatography has been developed. Elution of peroxydisulfate was effected by isocratic elution using 200 mM NaOH at 40 • C. A modification of the method using gradient elution was able to simultaneously determine other common inorganic ions (nitrate, nitrite, sulfate and chloride) down to significantly low concentrations in a peroxydisulfate matrix. The relative standard deviations (RSD) were in the range of 0.5-5%, for peak areas and <0.2% for peak retention times. The recoveries were between 95% and 120% for a concentration range of about 0.5-42 ppm. The limit of detection for peroxydisulfate ion was 0.2 ppm and for the other ions were ≤2 × 10 −2 ppm. The calibration curves were linear with slope and intercepts close to 1 and 0, respectively.
1989
In this paper, a novel method has been established to determine levodopa with the detection system of potassium ferricyanide-Fe(III). In the presence of potassium ferricyanide, it has been demonstrated that Fe(III) is reduced to Fe(II) by levodopa at pH 4.0. In addition, the in situ formed Fe(II) reacts with potassium ferricyanide to form soluble prussian blue (KFe III [Fe II (CN) 6 ]). Beer's law is obeyed in the range of levodopa concentrations of 0.01-4.00 mg mL-1 at the maximal absorption wavelength of 735 nm. The linear regression equation is A = 0.0082 + 0.61365 C (mg mL-1) with a correlation coefficient of 0.9996. The detection limit (3s/k) is 9 ng mL-1 , and R.S.D. is 0.73% (n = 11). Moreover, the apparent molar absorption coefficient of indirect determination of levodopa is 1.2´10 5 Lmol-1 cm-1. The parameters with regard to determination are optimized, and the reaction mechanism is discussed. This method has been successfully applied to determine levodopa in pharmaceutical, serum and urine samples. Analytical results obtained with this novel assay are satisfactory.
A rapid spectrophotometric determination of persulfate anion in ISCO
Chemosphere, 2008
Due to a gradual increase in the use of persulfate as an in situ chemical oxidation (ISCO) oxidant, a simple measurement of persulfate concentration is desirable to analyze persulfate distribution at designated time intervals on/off a site. Such a distribution helps evaluate efficacy of ISCO treatment at a site. This work proposes a spectrophotometric determination of persulfate based on modification of the iodometric titration method. The analysis of absorption spectra of a yellow color solution resulting from the reaction of persulfate and iodide in the presence of sodium bicarbonate reveals an absorbance at 352 nm, without significant interferences from the reagent matrix. The calibration graph was linear in the range of persulfate solution concentration of 0–70 mM at 352 nm. The proposed method is validated by the iodometric titration method. The solution pH was at near neutral and the presence of iron activator does not interfere with the absorption measurement. Also, analysis of persulfate in a groundwater sample using the proposed method indicates a good agreement with measurements by the titration method. This proposed spectrophotometric quantification of persulfate provides a simple and rapid method for evaluation of ISCO effectiveness at a remediation site.
Persulfate (peroxymonosulfate or peroxydisulfate) ions, as strong oxidants, have a broad application in the field of advanced oxidation processes (AOPs) for oxidative degradation of organic pollutants in soil and contaminated water. Persulfate concentration is an important operational parameter in persulfate degradation of organic pollutants based on SO 4 •−-AOPs. At present, the analytical methods used for quantification of persulfate mainly include traditional titration, polarography, electrochemiluminescence, electrochemical methods, spectrometry and chromatography. These methods vary in their limit of detection (LOD), execution time, operational difficulty, accuracy and sensitivity. The traditional methods are cheap and easy to operate, but the poor sensitivity and the high LOD limit its application. Electrochemiluminescence methods are highly sensitive with low detection limit, but requires rather specialized instruments. Electrochemical methods are repaid and have high sensitivity, low LOD and wide detection range, but relatively large reagent volume is needed in the determination process. Spectrophotometry has high accuracy with low consumption rate of sample and reagents, but it is susceptible to colored substances. Ion chromatography has the advantages of high sensitivity, less reagent consumption and simultaneous detection of multiple ions, but no advantage in detection time and LOD. This review presents the principles, merits and demerits of various existing analytical methods for persulfate determination, and discusses the limitations and applicability of various methods. This review is expected to provide some references for the establishment of novel detection methods for persulfate in the future.
Analytica Chimica Acta, 2002
The development of a highly sensitive method for the determination of nanomolar concentrations of hydrogen peroxide in the liquid phase is described. This paper demonstrates for the first time a flow injection analysis (FIA) system with immobilized enzyme reactor combined with a total internal reflective cell (a liquid waveguide capillary cell (LWCC)) and spectrophotometric detection, for the development of an improved procedure for the determination of hydrogen peroxide. Moreover, the newly synthesized 4-aminopyrazolone derivative, 4-amino-5-(p-aminophenyl)-1-methyl-2-phenyl-pyrazol-3-one (DAP), is used as a color coupler in its oxidative condensation with the sodium salt of N-ethyl-N-sulphopropylaniline sodium salt (ALPS) which acts as a hydrogen donor. Immobilization of peroxidase is achieved by coupling the periodate-treated enzyme to aminopropyl controlled-pore glass (CPG) beads. The determination of hydrogen peroxide is carried out in a 0.1 M phosphate buffer and the product is monitored at 590 nm with a charge-coupled device (CCD) detector equipped with fiber optics in a fully computerized system. The interference of different species, mainly ionic, was investigated.
In situ monitoring of peroxodisulfate anion production
Electroanalysis, 1997
A direct, continuous method for the measurement of peroxodisulfate anion has been devised and assessed. The approach is based upon the reduction of the anion under mass transfer limiting conditions at an amalgamated copper rotating disk electrode. The preparation of the disk electrode by Hg electroplating was examined in detail in order to generate a reproducible surface. The system was calibrated by demonstrating that the limiting current density for peroxodisulfate reduction was directly proportional to its bulk solution concentration. An electrochemical cell arrangement was then developed to permit the continuous, in situ measurement of peroxodisulfate concentration during electrochemical synthesis.
Using Fluorescence Spectroscopy to Assess Organic Matters in Activated Persulfate
Journal of Physics: Conference Series, 2020
Surface water contains organic matters from human activities, discharged industrial wastewater, and generated from microbial activities in water body. Persulfate is one of the strongest oxidants and could be used to oxidize organic matters. Fluorescence excitation emission matrices is one of the qualitative methods to identify organic matters properties, instead of chromatography and ultraviolet visible detection. The objective of this study was to identify dissolved organic matter in source and treated water by using peroxidation activated persulfate followed by coagulation. Sampel was analysed by using fluorescence excitation emission matrices (FEEMs) to assess its properties. The results showed that Activated persulfate has a good performance as pretreatment, in order to oxidize organic matters, further the coagulation is suitable treatment to combine with peroxidation activated persulfate. Those treatment resulted lower fluorescence intensity in all regions, including aromatic p...
Analytical Chemistry, 1991
The titie determination scheme has been developed for application to aqueous samples of importance to the petroleum industry. Sulfur(-11) is determined by acidification to produce H,S and gas diffusion into alkaline Na,[Fe(CN),NO]; in the same manifold, sulfur produced upon acidification from poiysulfides Is measured turbidimetrically and gives a measure of [S(O)]. Sulfite Is mesaured by acidification to produce SO,, gas diffusion, and bleaching of a pararosaniline receptor. Thiosulfate is measured by dialyzing the sample after on-line tretment with Zn2+ and HCHO and bleaching KMnO, with the dialyzate. Sulfate is measured by the turbidimetric BaSO, method; the fouHng of optical windows Is prevented by the use of a sheath-flow cuvette.
Spectrochimica Acta Part B: Atomic …, 2000
An automated on-line UV photooxidation with peroxodisulfate of some environmentally relevant organoarsenic and organotin compounds in a system built from commercially available modules has been studied and optimised with a view to both species-independent quantification of the total arsenic or tin in samples containing different Ž . organic species by flow injection hydride generation atomic absorption spectrometry FI᎐HGAAS and speciation Ž . analysis by coupled high-performance liquid chromatography HPLC with HGAAS detection. For organoarsenicals, the reaction with alkaline peroxodisulfate in a 10᎐15-m knotted reactor for ) 1.5 min insures ) 90% transformation Ž . of inorganic As III and six organoarsenic species to arsenate: monomethylarsonate, dimethylarsinate, arsenobetaine, arsenocholine, trimethylarsine oxide and tetramethylarsonium. For organotins, the UV photooxidation with acidic peroxodisulfate at 95᎐100ЊC provides recoveries of ) 80% for the inorganic tin, dimethyltin, trimethyltin, triethyltin, tripropyltin, triphenyltin, monobutyltin, dibutyltin and tributyltin but only approximately 15% for tetrabutyltin. The Ž .
The Analyst, 1990
A flow injection method of determining sulphite with amperometric monitoring of iodine using a single-channel manifold in which iodine is formed in the reverse flow injection (rFI) manner and reacts with sulphite dispersing in the normal flow injection (nFI) manner has been adapted for use with visible spectrophotometry. The carrier stream consists of an alkaline solution containing iodate and an excess of iodide: injections of acid and then of acidified sulphite are made. The decrease in the iodine signal (measured at 352 nm) i n the presence of sulphite is proportional to the sulphite concentration in the injectate. The alkalinity of the carrier stream was adjusted to reduce the signal widths and to prevent the appearance of double peaks. A rectilinear decrease in signal size (down t o ca. 10% of the signal size in the absence of sulphite) was obtained in the range 1 x 10-5-7 x l o-4~ sulphite using a single-channel manifold consisting of 3 m of 0.8 m m bore transmission tubing with a flow-rate of 5 m l min-1 and an injection volume of 15 yl, when the carrier stream was 6.7 x 10-6 M in iodate, 6.7 x 10-2 M in iodide and 3.5 x 10-3 M in sodium hydroxide, and the sample solution was 0.1 M in hydrochloric acid.