1 research outputs found
Multilayer Paper-Based Device for Colorimetric and Electrochemical Quantification of Metals
The
release of metals and metal-containing compounds into the environment
is a growing concern in developed and developing countries, as human
exposure to metals is associated with adverse health effects in virtually
every organ system. Unfortunately, quantifying metals in the environment
is expensive; analysis costs using certified laboratories typically
exceed $100/sample, making the routine analysis of toxic metals cost-prohibitive
for applications such as occupational exposure or environmental protection.
Here, we report on a simple, inexpensive technology with the potential
to render toxic metals detection accessible for both the developing
and developed world that combines colorimetric and electrochemical
microfluidic paper-based analytical devices (mPAD) in a three-dimensional
configuration. Unlike previous mPADs designed for measuring metals,
the device reported here separates colorimetric detection on one layer
from electrochemical detection on a different layer. Separate detection
layers allows different chemistries to be applied to a single sample
on the same device. To demonstrate the effectiveness of this approach,
colorimetric detection is shown for Ni, Fe, Cu, and Cr and electrochemical
detection for Pb and Cd. Detection limits as low as 0.12 μg
(Cr) were achieved on the colorimetric layer while detection limits
as low as 0.25 ng (Cd and Pb) were achieved on the electrochemical
layer. Selectivity for the target analytes was demonstrated for common
interferences. As an example of the device utility, particulate metals
collected on air sampling filters were analyzed. Levels measured with
the mPAD matched known values for the certified reference samples
of collected particulate matter