TY - JOUR
T1 - Detection of Cd, Pb, and Cu in non-pretreated natural waters and urine with thiol functionalized mesoporous silica and Nafion composite electrodes
AU - Yantasee, Wassana
AU - Charnhattakorn, Busarakum
AU - Fryxell, Glen E.
AU - Lin, Yuehe
AU - Timchalk, Charles
AU - Addleman, R. Shane
N1 - Funding Information:
This work was supported by extramural grant 5R21OH008900-02 from CDC's NIOSH and grant 1R21ES015620-01A1 from NIEHS. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of NIH. The research was performed in part at the Environmental Molecular Sciences Laboratory (EMSL), a DOE national scientific user facility located at PNNL. The authors thank Jarupa Kanlayanatham, Dr. Worapon Kiatkittipong, Dr. Joongjai Panpranot, Dr. Varong Pavarajan, Dr. Daniel J. Gaspar, and Dr. Karla Thrall for their contributions.
PY - 2008/7/14
Y1 - 2008/7/14
N2 - Electrochemical sensors have great potential for environmental monitoring of toxic metal ions in waters due to their portability, field-deployability and excellent detection limits. However, electrochemical sensors employing mercury-free approaches typically suffer from binding competition for metal ions and fouling by organic substances and surfactants in natural waters, making sample pretreatments such as wet ashing necessary. In this work, we have developed mercury-free sensors by coating a composite of thiol self-assembled monolayers on mesoporous supports (SH-SAMMS™) and Nafion on glassy-carbon electrodes. With the combined benefit of SH-SAMMS™ as an outstanding metal preconcentrator and Nafion as an antifouling binder, the sensors could detect 0.5 ppb of Pb and 2.5 ppb of Cd in river water, Hanford groundwater, and seawater with a minimal amount of preconcentration time (few minutes) and without any sample pretreatment. The sensor could also detect 2.5 ppb of Cd, Pb, and Cu simultaneously. The electrodes have long service times and excellent single and inter-electrode reproducibility (5% R.S.D. after 8 consecutive measurements). Unlike SAMMS™-carbon paste electrodes, the SAMMS™-Nafion electrodes were not fouled in samples containing albumin and successfully detected Cd in human urine. Other potentially confounding factors affecting metal detection at SAMMS™-Nafion electrodes were studied, including pH effect, transport resistance of metal ions, and detection interference. With the ability to reliably detect low metal concentration ranges without sample pretreatment and fouling, SAMMS™-Nafion composite sensors have the potential to become the next-generation metal analyzers for environmental and bio-monitoring of toxic metals.
AB - Electrochemical sensors have great potential for environmental monitoring of toxic metal ions in waters due to their portability, field-deployability and excellent detection limits. However, electrochemical sensors employing mercury-free approaches typically suffer from binding competition for metal ions and fouling by organic substances and surfactants in natural waters, making sample pretreatments such as wet ashing necessary. In this work, we have developed mercury-free sensors by coating a composite of thiol self-assembled monolayers on mesoporous supports (SH-SAMMS™) and Nafion on glassy-carbon electrodes. With the combined benefit of SH-SAMMS™ as an outstanding metal preconcentrator and Nafion as an antifouling binder, the sensors could detect 0.5 ppb of Pb and 2.5 ppb of Cd in river water, Hanford groundwater, and seawater with a minimal amount of preconcentration time (few minutes) and without any sample pretreatment. The sensor could also detect 2.5 ppb of Cd, Pb, and Cu simultaneously. The electrodes have long service times and excellent single and inter-electrode reproducibility (5% R.S.D. after 8 consecutive measurements). Unlike SAMMS™-carbon paste electrodes, the SAMMS™-Nafion electrodes were not fouled in samples containing albumin and successfully detected Cd in human urine. Other potentially confounding factors affecting metal detection at SAMMS™-Nafion electrodes were studied, including pH effect, transport resistance of metal ions, and detection interference. With the ability to reliably detect low metal concentration ranges without sample pretreatment and fouling, SAMMS™-Nafion composite sensors have the potential to become the next-generation metal analyzers for environmental and bio-monitoring of toxic metals.
KW - Cd
KW - Cu
KW - Electrochemical sensor
KW - Nafion
KW - Natural water
KW - Pb
KW - Self-assembled monolayers on mesoporous supports
KW - Thiol
KW - Urine
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U2 - 10.1016/j.aca.2008.05.029
DO - 10.1016/j.aca.2008.05.029
M3 - Article
C2 - 18558124
AN - SCOPUS:46549087760
SN - 0003-2670
VL - 620
SP - 55
EP - 63
JO - Analytica Chimica Acta
JF - Analytica Chimica Acta
IS - 1-2
ER -