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N,N-Diethyl-p-phenylenediamine (DPD)

Jing Zou, Huahua Cai, Daiyao Wang, Junyang Xiao, Zhenming Zhou, Baoling Yuan
A low-cost and environmentally-friendly spectrophotometric method for hydrogen peroxide (H2 O2 ) determination based on the oxidative coloration reaction of N,N'-diethyl-p-phenylenediamine (DPD) via the Fenton reactions in aqueous water was established. The generated pink radical cation (DPD+ ) showed maximum absorption at 551 nm. Importantly, under the optimal conditions (pH 3.0, 20 mM DPD, 1.5 mM Fe(II) and reaction time of 45 s), the increase in absorbance at 551 nm for DPD+ generation was linear with respect to the addition of H2 O2 (0-12 μM)...
March 2, 2019: Chemosphere
Ladan Esmaeili, Mariela Gomez Perez, Maziar Jafari, Joanne Paquin, Pompilia Ispas-Szabo, Veronica Pop, Marius Andruh, Joshua Byers, Mircea Alexandru Mateescu
Copper coordinated with amino acid residues is essential for the function of many proteins. In addition, copper complexed to free l-Histidine, as [Cu(His)2 ], is used in the treatment of the neurodegenerative Menkes disease and of cardioencephalomyopathy. This study was aimed to coordinate copper(II) with four small ligands (l-Serine, l-Histidine, Urea and Biuret) and to evaluate structural features, stability, antioxidant activity and neuronal compatibility of the resulting complexes. All complexes were synthesized with CuCl2 and purified by precipitation in alcohol...
December 26, 2018: Journal of Inorganic Biochemistry
Peng Li, Takeshi Yoshimura, Takeshi Furuta, Toshiharu Yanagawa, Keiko Shiozaki, Takuya Kobayashi
Chlorination is the most common method to control water qualities, in some case on-site outdoor measurements are required to measure easily-decaying residual chlorine concentration appropriately without delay. In this study sunlight-induced unexpected colour development (UCD) of N, N-diethyl-p-phenylenediamine (DPD) colorimetric measurement was studied under several sun exposure conditions. The colour development level was evaluated with reference to chlorine concentration (mg/L) and relationships between colour development rate (mg/L min) and intensities of solar were investigated...
November 26, 2018: Ecotoxicology and Environmental Safety
Xin Liu, Huahua Cai, Jing Zou, Zijun Pang, Baoling Yuan, Zhenming Zhou, Qingfeng Cheng
A sensitive spectrophotometric method (the N,N-diethyl-p-phenylenediamine (DPD) method) was established for the determination of trace permanganate concentration (0-10 μM) in water. The DPD method was based on the oxidative coloration reaction where permanganate could oxidize DPD to form the red colored DPD radical (DPD•+ ) with a second-order rate constant of 2.96 × 104  M-1  s-1 at pH 6 (50 mM phosphate buffer). The generated DPD•+ could be quantitatively measured at 551 nm using an UV-Vis spectrophotometer...
December 2018: Chemosphere
Yan Xiong, Jun Tan, Shenwen Fang, Chengjie Wang, Qing Wang, Jiayi Wu, Jie Chen, Ming Duan
In this work, a colorimetric methodology was developed for free chlorine determination by constructing a fiber-optic sensor (FOS) which was designed by using a small LED as light source and two silica fibers as light transmission elements. Then the FOS was integrated with the sequential injection lab-on-valve (SI-LOV) manifold to fabricate a FOS-SI-LOV system for free chlorine detection. The colorimetric determination was based on the reaction between N,N-diethyl-p-phenylenediamine (DPD) reagent and free chlorine, which would produce a chromophore showing maximum absorbance at 511 and 551nm and detected by a micro spectrometer detector...
May 15, 2017: Talanta
T A Ammar, K Y Abid, A A El-Bindary, A Z El-Sonbati
Most drinking water industries are closely examining options to maintain a certain level of disinfectant residual through the entire distribution system. Chlorine dioxide is one of the promising disinfectants that is usually used as a secondary disinfectant, whereas the selection of the proper monitoring analytical technique to ensure disinfection and regulatory compliance has been debated within the industry. This research endeavored to objectively compare the performance of commercially available analytical techniques used for chlorine dioxide measurements (namely, chronoamperometry, DPD (N,N-diethyl-p-phenylenediamine), Lissamine Green B (LGB WET) and amperometric titration), to determine the superior technique...
December 2015: Journal of Water and Health
H Yamaoka, H Nakayama-Imaohji, I Horiuchi, H Yamasaki, T Nagao, Y Fujita, H Maeda, H Goda, T Kuwahara
UNLABELLED: Chlorine is a principal disinfectant for food and environmental sanitation. Monitoring of free available chlorine (FAC) is essential for ensuring the efficacy of food disinfection processes that rely on chlorine. N,N-diethyl-p-phenylenediamine (DPD) is commonly used for FAC monitoring. However, here, we show that upon contact with bovine serum albumin (BSA) or broiler carcasses, chlorite (HClO2 )-based sanitizers acquire a pink colour, which can interfere with measurement of oxidized DPD absorbance at 513-550 nm...
January 2016: Letters in Applied Microbiology
Yi He, Haili Yu
In this study, a novel assay for the detection of free chlorine is proposed for the first time. It is based on a redox reaction that occurs between triangular silver nanoprisms and free chlorine, which results in a morphological transformation and a change of the localized surface plasmon resonance (SPR) of the triangular silver nanoprisms. In the assay, the presence of free chlorine would etch triangular silver nanoprisms from triangle to round, leading to a significant blue-shift SPR absorption band of triangular silver nanoprisms...
February 7, 2015: Analyst
Amity G Zimmer-Faust, Richard F Ambrose, Mario N Tamburri
With the maturation and certification of several ballast water management systems that employ chlorine as biocide to prevent the spread of invasive species, there is a clear need for accurate and reliable total residual oxidants (TRO) technology to monitor treatment dose and assure the environmental safety of treated water discharged from ships. In this study, instruments used to measure TRO in wastewater and drinking water applications were evaluated for their performance in scenarios mimicking a ballast water treatment application (e...
2014: Water Science and Technology: a Journal of the International Association on Water Pollution Research
Hsin-Se Hsieh, Renren Wu, Chad T Jafvert
Promising developments in application of carbon nanotubes (CNTs) have raised concern regarding potential biological and environmental effects upon their inevitable release to the environment. Although some CNTs have been reported to generate reactive oxygen species (ROS) under light, limited information exists on ROS generation by these materials in the dark. In this study, generation of ROS was examined, initiated by electron transfer from biological electron donors through carboxylated single-walled carbon nanotubes (C-SWCNT) to molecular oxygen in water in the dark...
October 7, 2014: Environmental Science & Technology
Dean Song, Huijuan Liu, Zhimin Qiang, Jiuhui Qu
Free chlorine is extensively used for water and wastewater disinfection nowadays. However, it still remains a big challenge to determine the rate constants of rapid chlorination reactions although competition kinetics and stopped-flow spectrophotometric (SFS) methods have been employed individually to investigate fast reaction kinetics. In this work, we proposed an SFS competition kinetics method to determine the rapid chlorination rate constants by using a common colorimetric reagent, N,N-diethyl-p-phenylenediamine (DPD), as a reference probe...
May 15, 2014: Water Research
Marcelo B Lima, Inakã S Barreto, Stéfani Iury E Andrade, Luciano F Almeida, Mário C U Araújo
In this study, a micro-flow-batch analyzer (μFBA) with solenoid micro-pumps for the photometric determination of iodate in table salt is described. The method is based on the reaction of iodate with iodide to form molecular iodine followed by the reaction with N,N-diethyl-p-phenylenediamine (DPD). The analytical signal was measured at 520 nm using a green LED integrated into the μFBA built in the urethane-acrylate resin. The analytical curve for iodate was linear in the range of 0.01-10.0 mg L(-1) with a correlation coefficient of 0...
October 15, 2012: Talanta
Yongqiang Dong, Geli Li, Nana Zhou, Ruixue Wang, Yuwu Chi, Guonan Chen
Free chlorine was found to be able to destroy the passivated surface of the graphene quantum dots (GQDs) obtained by pyrolyzing citric acid, resulting in significant quenching of their fluorescence (FL) signal. After optimizing some experimental conditions (including response time, concentration of GQDs, and pH value of solution), a green and facile sensing system has been developed for the detection of free residual chlorine in water based on FL quenching of GQDs. The sensing system exhibits many advantages, such as short response time, excellent selectivity, wide linear response range, and high sensitivity...
October 2, 2012: Analytical Chemistry
S-C Weng, W A Weaver, M Zare Afifi, T N Blatchley, J S Cramer, J Chen, E R Blatchley
UNLABELLED: Trichloramine (NCl(3)) is recognized as an irritant of the human respiratory system and other tissues. Processes that lead to volatilization from the liquid phase allow for human exposure to gas-phase NCl(3) in swimming pool settings. The dynamics of these processes are not well defined. A N,N-diethyl-p-phenylenediamine/potassium iodide (DPD/KI)-based wet-chemistry method for measuring gas-phase NCl(3) concentration was verified and applied in chlorinated, indoor swimming pool facilities...
October 2011: Indoor Air
M Fukushima, K Tatsumi
The influence of dissolved organic matter (DOM), such as humic acid (HA) and hydroxybenzoic acids, on the determination of H(2)O(2) via a colorimetric method using N,N-diethyl-p-phenylenediamine (DPD) was examined. The influence of DOM on absorbance decay at 551 nm, which represents the wavelength for maximum absorption of the oxidized species of DPD (DPD(+)), were investigated in detail. Significant decrease in the absorbance at 551 nm was observed in the presence of HA and gallic acid. This resulted in a fadeout of the purple color of DPD(+), which, in term, created great difficulties in the measurement of H(2)O(2) in solutions which contain DOM...
November 1998: Talanta
D Johnson, B Chiswell
The suitability of application of a number of previously used methods for the evaluation of the oxidizing equivalent (OE) of manganese in natural waters is compared with a new method, which depends upon colour development of the dye N,N'-diethyl-p-phenylenediamine (DPD) upon oxidation by oxidized forms of manganese. The effect of introducing a commonly used metabolic poison, azide, into the most reliable of these determinations of OE has also been assessed.
April 1993: Talanta
G Gordon, D L Sweetin, K Smith, G E Pacey
In the determination of free and combined chlorine, the reaction of permanganate standards with N,N-diethyl-p-phenylenediamine (DPD) exhibits nonlinearity presumably because both the colored semiquinoid product and the colorless quinoid product are both formed. The titrimetric DPD method titrates both of the products while the colorimetric method monitors only the colored semiquinoid products. This results in a nonlinear response for the colorimetric method above 1.0 mg/l. as Cl(2). Under FIA conditions, the nonlinearity of the DPD colorimetric method is eliminated in the 0...
February 1991: Talanta
Wei Luo, M E Abbas, Lihua Zhu, Kejian Deng, Heqing Tang
In this study, a sensitive and rapid method for hydrogen peroxide (H(2)O(2)) determination has been developed with the aid of oxidation decolorization of methyl orange (MO) by using Fenton reactions, because the decolorization extent of MO solution (at the maximum absorption wavelength of 507 nm) is proportion to the concentration of H(2)O(2). Under optimum conditions, this spectrophotometric method for the H(2)O(2) analysis yields a dynamic range of H(2)O(2) concentration from 5.0 x 10(-7) to 1.0 x 10(-4) mol L(-1) (r=0...
November 23, 2008: Analytica Chimica Acta
Ashraf A Mohamed, Ahmed T Mubarak, Zakaria M H Marestani, Khaled F Fawy
A highly sensitive, simple and selective kinetic method was developed for the determination of ultra-trace levels of formaldehyde and acetaldehyde based on their catalytic effect on the oxidation of N,N-diethyl-p-phenylenediamine (DPD) with hydrogen peroxide. The reaction was monitored spectrophotometrically by tracing the formation of the red-colored oxidized product of DPD at 510nm, within 30s of mixing the reagents. The optimum reaction conditions were: 20mmolL(-1) DPD, 250mmolL(-1) H(2)O(2), 150mmolL(-1) phosphate, 150mmolL(-1) citrate and pH 6...
January 15, 2008: Talanta
Sivanildo da Silva Borges, Boaventura F Reis
In this work an automatic photometric procedure for the determination of chlorine in bleach samples employing N,N'-diethyl-p-phenylenediamine (DPD) as chromogenic reagent is described. The procedure was based on a falling drop system where the analyte (Cl(2)) was collected by a DPD solution drop (50 microL) after its delivery from the sample bulk that was previously acidified. The flow system was designed based on the multicommutation process assembling a set of three-way solenoid valves, which under microcomputer control afforded facilities to handle sample and reagent solution in order to control analyte delivering and solution drop generation...
September 26, 2007: Analytica Chimica Acta
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