Nanochemistry Research Institute, Department of Chemistry, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Anal Bioanal Chem. 2013 Apr;405(11):3801-6. doi: 10.1007/s00216-012-6622-2. Epub 2012 Dec 14.
The behaviour of haemoglobin (Hb) at the interface between two immiscible electrolyte solutions (ITIES) has been examined for analytical purposes. When Hb is fully protonated under acidic conditions (pH <pI) in the aqueous phase, it undergoes a potential-dependent adsorption and complexation, at the interface, with the anions of the organic phase electrolyte. When utilised as a simple and fast preconcentration step, consisting of adsorbing the protein at the interface, in conjunction with voltammetric desorption, this opens up the ITIES to the adsorptive stripping voltammetry approach. Utilising a 60 s adsorption step and linear sweep voltammetry, a linear response to Hb concentration in aqueous solution over the range 0.01-0.5 μM was achieved. The equation of the best-fit straight line was I(p) = 7.46 C - 0.109, R = 0.996, where I(p) is the peak current (in nanoampere) and C is haemoglobin concentration (in micromolar). The calculated detection limit (3σ) was 48 nM for a 60 s preconcentration period, while the relative standard deviation was 13.3% for six successive measurements at 0.1 μM Hb. These results illustrate the prospects for simple, portable and rapid label-free detection of biomacromolecules offered by electrochemistry at arrays of liquid-liquid microinterfaces.
已经研究了血红蛋白（Hb）在两种不混溶电解质溶液（ITIES）界面处的行为，以便进行分析。当 Hb 在酸性条件下（pH < pI）完全质子化时，它在界面处与有机相电解质的阴离子发生电位依赖性吸附和络合。当用作简单快速的预浓缩步骤，包括在界面处吸附蛋白质，并结合伏安法解吸时，这就为 ITIES 开辟了吸附剥离伏安法的途径。利用 60 秒的吸附步骤和线性扫描伏安法，在 0.01-0.5 μM 的水溶液中 Hb 浓度范围内实现了对 Hb 浓度的线性响应。最佳拟合直线的方程为 I(p) = 7.46 C - 0.109，R = 0.996，其中 I(p)是峰电流（纳安培），C 是血红蛋白浓度（微摩尔）。对于 60 秒的预浓缩时间，计算出的检测限（3σ）为 48 nM，而在 0.1 μM Hb 时，连续六次测量的相对标准偏差为 13.3%。这些结果说明了电化学在液体-液体微界面阵列中提供的简单、便携和快速生物大分子无标记检测的前景。
