科研之友
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摘要
A novel method of real-time-range measurement, characterized by pre-sampling forecast and balanced-range switching, is introduced in this study. According to this method, raw current signals in biosensing procedures may be measured and recorded with real-time-optimized instrumental settings. A low-cost and high-performance potentiostat is developed to validate the proposed method. The transient process of real-time-range measurement is investigated to optimize sampling interval and circuit parameters. Typical time consumption of a sampling cycle is less than 100 mu s, which makes high-speed and real-time-range measurement possible. The proposed method also brings excellent current resolution that is better than 0.8 pA. It improves weak signals in stripping determinations, and is particularly suitable for biological samples. As-fabricated potentiostat, coupled to a nano-Au-modified microband electrode array, is adopted in high-speed stripping determinations towards human blood lead levels (HBLLs). Accuracy and precision of this method are validated with certified reference material (CRM). Obtained values (4.31 +/- 0.18 mu g L-1) meet with certified levels of CRM (4.24 +/- 0.11 mu g L-1). Coefficient of variation percent (CV %) is no more than 5.0% for intra- or inter-assay analyses. Finally, this method is utilized for human population based study. Two groups of data, from this method and inductively coupled plasma mass spectrometry (ICP-MS), are analyzed using a statistic tool of t-test, and no statistically significant difference is found.
