采用透析-高效液相色谱-氢化物发生-原子荧光光谱联用法研究了生理pH(7.4)条件下As(Ⅲ)或/和As(Ⅴ)与牛血清白蛋白的结合平衡模型.当As(Ⅲ)浓度[CAs(Ⅲ):CBSA≤1:1]较低时,As(Ⅲ)与BSA的结合符合Scatchard模型,在BSA中有1.4个强结合部位,结合常数为1.7×10^6;当As(Ⅲ)的浓度[CAs(Ⅲ):CBA≥2:1]较高时,符合Plasvento的相分配模型,没有明显的特征结合点,而As(Ⅴ)与BSA无任何结合作用.研究了HCl和KBH4的浓度和流速等对色谱分离的影响,并对检测器参数等实验条件进行了优化,使不同价态无机砷在10min内达到良好的基线分离,As(Ⅲ)和As(Ⅴ)的检测限分别为2.89和6.38ng/L.
The binding equilibrium of As ( Ⅲ)/As ( Ⅴ ) to bovine serum albumin (BSA) was studied by Dialysis and High Performance Liquid Chromatography-hydride generation on-line coupled with atomic fluorescence spectrometry(D-HPLC-HG-AFS) at physiological (pH = 7.4). The binding plots analysis indicates that the binding model is Scatchard when the concentrations of As ( Ⅲ ) ions are lower [ CAs(Ⅲ) : CBA≤ 1 : 1 ], there is 1.4 strong binding site of As (Ⅲ) ions in BSA, the stability constants is 1.7 × 10^6 at physiological (pH = 7.4). The binding model is Plasvento when the concentrations of As( Ⅲ ) ions are higher( CAs〈 Ⅲ): CBSA ≥2:1 ], and As( Ⅴ ) ions has litter effect on BSA. The method based on HPLC-HG-AFS for arsenic speciation analysis was developed. The factors of the method including HPLC mobile phase, concentrations of HCl, flow rate of HCl, concentration and flow rate of KBH4 were investigated in this paper. Under the optimum conditions, the detection limits for As( Ⅲ) and As( Ⅴ ) were 2. 89, 6.38 ng/L, respectively.