Rapid Voltammetric Diagnosis of <italic>Escherichia Coli</italic> Contamination in Non-Treated Human Blood Plasma of Healthy and Sepsis-Infected Patients

Abstract

Escherichia coli ( E. coli ) contamination, a critical indication of sepsis-infection, was detected rapidly in real-time using cyclic voltammetry and square wave stripping voltammetry. Mercury-immobilized carbon nanotube paste working electrode and cost-efficient pencil-rod graphite counter and reference electrodes were used and compared with common-type metal and catalytic probes. Electrolyte solutions that were directly utilized included purified seawater, non-treated healthy human blood plasma, and sepsis-infected blood plasma, where cyclic reaction potential was obtained with +0.2-V oxidation and anodic stripping potential of 0.0–4.0-mL E. coli . The analytical interference effects for in vivo trace metals and other microorganisms were determined. Under optimized stripping conditions, a statistic SW detection limit of 0.08 mg L−1 E. coli was obtained. Diagnostic application was successfully performed on sepsis-infected blood plasma, wherein peak current trend and final para-strength were shown to be in accordance with the linear working-range attained. These methodologies and results are applicable for direct in vitro and in vivo real-time detection of E. coli with optimal cost- and time-efficiency.