Study on the Indirect Determination of Chitosan by Square Wave Voltammetry

建立了以茜素红(AR)为电活性探针方波伏安法间接测定无电活性的壳聚糖(CS)的新方法。在0 1mol/LHAc＿NaAc(pH4 5)缓冲溶液中,AR与CS＿AR在GCE上均能形成一准可逆的吸附伏安峰(Vpc=-0 46V,Vpa=-0 41V)。实验表明,CS在低浓度(1 25×10-8～2 5×10-7mol/L)和高浓度(2 5×10-7～1 25×10-5mol/L)的条件下对体系的峰电流分别具有线性增敏和减敏效应。采用标准加入法测定了不同样品中壳聚糖的含量,其回收率在97 33%～102 00%之间,结果满意。广西壮族自治区自然科学基金资助项目(0141037;0342018

Study on the Determination of Chitosan by Using Alizarin Red as An Electrochemical Activity Probe

建立了以茜素红(AR)为电活性探针间接测定无电活性壳聚糖(CS)的新方法。研究了AR及其与CS的结合物AR-CS于0.1 mol/L HAc-NaAc(pH 4.5)缓冲溶液中在玻碳电极(GCE)上的电化学行为。AR与CS-AR在GCE上均能形成一准可逆的吸附伏安峰(Vpc=-0.46 V,Vpa=-0.41 V,ΔVp=0.05 V)。测定了X、α、Ks等电化学参数。实验表明,CS在低浓度(1.25×10-8~2.5×10-7mol/L)和高浓度(2.5×10-7~1.25×10-5mol/L)的条件下对体系的峰电流分别具有线性增敏和减敏效应。采用标准加入法测定了不同样品中壳聚糖的含量,其回收率在97%~102%之间,结果满意。 A new method to determine chitosan （CS） indirectly was established by using alizarin red （AR） as an electrochemical activity probe. The electrochemical behaviour of the interaction between AR and CS was investigated in 0. 1 mol/L HAc - NaAc buffer solution（pH 4.5） on the glassy carbon electrode（GCE） by voltammetry. The results show that AR and AR - CS complex can be easily reduced or oxidized on the GCE and they have a pair of well-defined quasi-reversible waves （ Vpc = -0.45 V, Vpa =-0.41V, △ Vp =0. 04 V） with adsorption characteristics. The electrochemical parameters such as proton numbers （X）, electron transfer coefficient（α）, reaction rate constant（K） were measured by cyclic voltammetry. The increase and decrease of reductive peak currents of AR are proportional to CS concentration in the range of 1.25 × 10^-8 - 2.5 × 10^- 7 mol/L and 2.5 ×10^-7- 1.25×10^-5 mol/L, respectively. The method has been successfully used for the determination of CS in different samples by standard addition. The recovery was measured to be 97% - 102%.国家自然科学基金资助项目(20475068);广西壮族自治区自然科学基金资助项目(0141037,0342018

Electrochemical Behaviour of the Interaction Between Chitosan and Al izarin

Abstract　The interaction betw een Ali zarin red ( AR) and Chi tosan ( CS) w as inv estigated in 0. 1 mol /L HAc-NaAc buf fer solution ( pH= 4. 5) on the glassy carbo n elect rode ( GC) by cyclic and square wave voltammet ry. The results show that bo th AR and AR-CS complex have a well-defined quasi-rev ersible redox wave( Vpc= - 0. 46 V , Vpa= - 0. 41 V ) with adsorption characteristics. Electron t ransfer coefficient (T) and reaction rate constant (Ks ) of AR and AR-CS were measured by cyclic voltammet ry. The maximum binding numbers m betw een AR and CS was found to be 2 500. The ex periment results confirmed that low er concentratio n of CS can enhance the detection sensitivity , w hile hig her concent ration of CS can low er the detection sensitivi ty. In the presence of 2. 0× 10- 5 mol /L AR, the peak current of sy stem are proportional to CS concentration in the rang e of 1. 25× 10- 8～ 2. 5× 10- 7 mol /L, and inv ersely proportional to CS concentration in the rang e of 2. 5× 10- 7～ 1. 25× 10- 5 mol /L, respectiv ely. The binding interaction mechanism w as also discussed.国家自然科学基金(批准号:20475068);广西壮族自治区自然科学基金(批准号:0141037,0342018)资