Method Of Simultaneous Determination Of Hydroquinone And Catechol By Adjusting The Electrode Interface PH

Hydroquinone and catechol are widely used in many fields,such as:textile industry,chemical industry,pharmaceutical manufacturing,etc.In these processes,hydroquinone and catechol inevitably flow into the living environment.Due to its high toxicity and low degradation,and harm to the environment and organisms,hydroquinone and catechol have received extensive attention.Therefore,it is a meaningful work to detect the content of hydroquinone and catechol.At present,the methods for detecting hydroquinone and catechol mainly include spectrophotometry,chemical luminescence,and high performance liquid chromatography（HPLC）.However,these methods have some limitations,such as long time-consuming,more complex sample processing,and expensive instruments.Therefore,it is necessary to establish a new method for simultaneous determination of hydroquinone and catechol.Hydroquinone and catechol have been widely studied.The redox reaction process is essentially proton-coupled electron transfer（PCET）.Cyclic voltammetry and differential pulse voltammetry are effective methods for the study of proton-coupled electron transfer.We studied the cyclic voltammetric behavior of hydroquinone and catechol in aqueous solution.In the low concentration of dilute phosphate buffer solution,two pairs of redox peaks appear,increasing the concentration of phosphate buffer,when the concentration of HPO₄^2-is equal to twice that of hydroquinone or catechol,only one pair of broad redox peaks appears for hydroquinone or catechol.When hydroquinone and catechol were simultaneously added in a dilute phosphate buffer solution and the concentration of disodium hydrogen phosphate and the concentration of the concentration of HPO₄^2-is equal to twice that of hydroquinone,the peak separation between hydroquinone and catechol reach the largest.In this paper,we determined the hydroquinone and catechol at the same time When the concentration of disodium hydrogen phosphate was twice that of HQ.Differential pulse voltammetry was used to measure Hydroquinone and catechol simultaneously.It was found that Hydroquinone and catechol did not interfere with each other,and the peak current value of the oxidation peak had a good linear relationship with its corresponding concentration.Secondly,pH controlling the rate of adduct reaction of glutathione with p-benzoquinone and o-benzoquinone,we found that at pH 3.9,the addition reaction of glutathione to p-benzoquinone is completely suppressed but the adduct reaction with o-benzoquinone is rapid.Using the above characteristics,a method for the determination of hydroquinone and catechol can be established.We use the differential pulse voltammetry differential pulse to carry out the simulated sample.The results show that the method is simple and reproducible,which shows that this method is practical.