Hybrid Electrochemical-Piezoelectric Sensor for RCRA Metals in Groundwater: Detection of Hexavalent Chromium

EPA Contract Number: 68D99077
Title: Hybrid Electrochemical-Piezoelectric Sensor for RCRA Metals in Groundwater: Detection of Hexavalent Chromium
Investigators: Andle, Jeffrey C.
Small Business: BIODE Inc.
EPA Contact: Richards, April
Phase: II
Project Period: September 1, 1999 through September 1, 2001
Project Amount: $224,155
RFA: Small Business Innovation Research (SBIR) - Phase II (1999) Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , SBIR - Monitoring , Small Business Innovation Research (SBIR)


BIODE is developing a hybrid sensor that combines the sensitivity of piezoelectric nanobalance technology with the selectivity of stripping potentiometric analysis for the detection of heavy metals in aqueous samples. Prior SBIR effort has resulted in a single sensor that is capable of parts-per-billion levels of ionic mercury. By improving the electrochemical circuitry and using suitable electrode modification, the technique is being extended to the detection and speciation of additional toxic heavy metals. The long-term goal is an array of electrochemical nanobalances for the simultaneous detection and speciation of all Resource Conservation and Recovery Act (RCRA) metals.

Phase I of the proposed effort focused on demonstrating the feasibility of this sensor technology for the speciation of ionic Chromium. In addition, Phase I demonstrated the ability to detect carcinogenic Chromium (VI) while distinguishing it from the essential nutrient, Chromium (III), and the species already detectable by the sensor, Mercury (II).

Phase II will pursue improved sensitivity and increased integration of the prototype. In particular, surface transverse wave (STW) technology offers a hundredfold sensitivity improvement while offering substantial size reductions. Application-specific integrated circuits (ASIC) development will improve reliability while decreasing size and cost. Finally, matrix and interferent effects will be explored for typical aqueous detection applications.

The proposed Phase II effort will result in a small prototype of a highly sensitive chromate sensor. Phase I effort has demonstrated the feasibility of the technology. Phase II effort will increase sensitivity, develop a completed prototype, and obtain essential test data. The result of the Phase II project will be a prototype sensor and the performance data necessary for commercialization funds.

Commercial applications exist in environmental testing and wastewater treatment in present and past industrial sites in which chromate has been employed. Chromate has been extensively employed by the aerospace and electronics industry and is especially associated with aircraft maintenance.

The proposed Phase II effort may be expanded to multiple heavy metals and other ionic toxins, offering vastly expanded commercialization opportunities in water quality testing. These might include drinking water testing (e.g., mercury, lead, cadmium, chromate, perchlorate), blood testing (e.g., lead), environmental screening, nuclear plant safety, and nuclear nonproliferation treaty verification.

Supplemental Keywords:

small business, SBIR, monitoring, analytical, engineering, chemistry, EPA., RFA, Scientific Discipline, Toxics, Water, Ecosystem Protection/Environmental Exposure & Risk, mercury transport, Chemistry, Monitoring/Modeling, Analytical Chemistry, 33/50, Engineering, Chemistry, & Physics, Mercury, aquatic ecosystem, environmental monitoring, fate and transport, electrochemical technology, chromium & chromium compounds, aqueous mercury, electrochemical , Chromium, metal ions, stripping potentiometric analysis, mercury & mercury compounds, electrochemical analysis, piezoelectric, electrochemical sensor, Piezoelectric sensor, sensor, sensor technology, heavy metals, metals

Progress and Final Reports:

  • Final Report

  • SBIR Phase I:

    Hybrid Electrochemical-Piezoelectric Sensor for RCRA Metals in Groundwater: Detection of Hexavalent Chromium  | 1998 Progress Report  | Final Report