Abstract:This work deals with a portable device system applied to detect and classify different metallic ions as proposed and developed, aiming its application for hydrological monitoring systems such as rivers, lakes and groundwater. Considering the system features, a portable colorimetric system was developed by using a multispectral optoelectronic sensor. All the technology of quantification and classification of metallic ions using optoelectronic multispectral sensors was fully integrated in the embedded hardware F… Show more
“…The devices come with precalibrated settings for specific substances, ensuring accurate and reliable measurements. 38,39 Fig. 1 illustrates the graphical scheme of a portable colorimetric device where the concentration of a chemical substance in an unknown sample solution can be directly monitored from the sample sites.…”
Developement of portable colorimetric devices for detection of heavy metals, anions, biomolecules, pesticides, drugs, and other substances is vital across clinical, environmental, and food safety domains.
“…The devices come with precalibrated settings for specific substances, ensuring accurate and reliable measurements. 38,39 Fig. 1 illustrates the graphical scheme of a portable colorimetric device where the concentration of a chemical substance in an unknown sample solution can be directly monitored from the sample sites.…”
Developement of portable colorimetric devices for detection of heavy metals, anions, biomolecules, pesticides, drugs, and other substances is vital across clinical, environmental, and food safety domains.
“…This approach is able accommodate more sensing mechanisms than single spectral band approach especially in application that have multiple spectral band of interest. [27]. The RGB color light pulses are generated by the FPGA using pulse width modulation (PWM).…”
Section: B Readout Systemmentioning
confidence: 99%
“…The digital waveforms stored in the FPGA's RAM are generated beforehand and addressed during operation [29]. An arbitrary light waveform may be useful in applications such as in the case of lock-in signal detection [30], fluorescent measurement [27] and laser diode wavelength tuning. In the case of this investigation, the three PWM output configuration was used solely for switching and intensity control purpose.…”
Section: B Light Source and Photodetector Designmentioning
This work presents the realization of a surface Plasmon resonance (SPR) sensor readout system using a tricolor red, green and blue (RGB) light emitting diode (LED) light source. Time domain intensity modulation of each color channel is applied to interrogate three bands of interest in the SPR spectrum using a single photodiode detector. A low computing resource classification approach is used through the combination of k-nearest neighbor (kNN) and adapted clustering using representative (CURE). An optimized number of representatives is chosen in the validation process to reduce the required amount of data for the kNN classification. This scheme was used to classify the concentrations of different glucose solutions. The sensor readout system hardware is based on the use of a field programmable gate array (FPGA) and the glucose solution classification is developed and undertaken on a personal computer (PC) using the Python open source programming language.
“…Owing to the simple configuration and small size, electrochemical and colorimetric analysis methods have been adopted for on-site heavy metal detection. In addition, these methods facilitate a more sensitive detection of multiple heavy metal ions at a lower cost, as compared to that of the portable XRF spectrometry [ 10 , 11 , 12 ]. Recently, Ying Gan et al reported the successful detection of cadmium at concentrations as low as 1.12 ppb, using a colorimetric method; this concentration is much lower than the EPA standard for cadmium concentration in drinking water [ 13 ].…”
This article presents the development of a highly sensitive electrochemical heavy metal sensor based on hierarchical porous carbon electrodes with sponge-like edge structures. Micrometer-scale hierarchical nanoporous carbon electrodes were fabricated at a wafer-scale using cost-effective batch microfabrication technologies, including the carbon microelectromechanical systems technology and oxygen plasma etching. The sponge-like hierarchical porous structure and sub-micrometer edges of the nanoporous carbon electrodes facilitate fast electron transfer rate and large active sites, leading to the efficient formation of dense heavy metal alloy particles of small sizes during the preconcentration step. This enhanced the peak current response during the square wave anodic stripping voltammetry, enabling the detection of Cd(II) and Pb(II) at concentrations as low as 0.41 and 0.7 μg L−1, respectively, with high sensitivity per unit sensing area (Cd: 109.45 nA μg−1 L mm−2, Pb: 100.37 nA μg−1 L mm−2).
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