Multifunctional Water Sensors for pH, ORP, and Conductivity Using Only Microfabricated Platinum Electrodes

Lin, Wen Chi; Brondum, Klaus; Monroe, Charles W.; Burns, Mark A.

doi:10.3390/s17071655

Cited by 24 publications

(11 citation statements)

References 29 publications

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“…In particular, a communication system that exchanges information to respond immediately to sensor failures on-site is required. Many researchers have reported that the previously mentioned diagnostic systems create synergies when combined with Internet-of-Things (IoT) technology; in addition, IoT has been applied in many recent sensing technology studies [ 18 , 19 , 20 ]. These technologies primarily form part of a system such as an automatic on-site water quality measurement, a data logging, and wireless communication system.…”

Section: Introductionmentioning

confidence: 99%

Water Nitrate Remote Monitoring System with Self-Diagnostic Function for Ion-Selective Electrodes

Park

Kim

et al. 2021

Sensors

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The detection of nitrate pollutants is a widely used strategy for protecting water sources. Although ion-selective electrodes (ISEs) have been considered for the determination of ion concentrations in water, the accuracy of ISE technology decreases owing to the signal drift and decreasing sensitivity over time. The objectives of the present study were: (1) to develop an online water monitoring system mainly consisting of an Arduino board-based Internet-of-Things (IoT) device and nitrate ISEs; and (2) to propose a self-diagnostic function for monitoring and reporting the condition of the ISEs. The developed system communicates with the cloud server by using the message queuing telemetry transport (MQTT) protocol and provides monitoring information through the developed cloud-based webpage. In addition, the online monitoring system provides information on the electrode status, which is determined based on a self-diagnostic index (SDI, with a range of 0–100) of the electrode drift and sensitivity. The diagnostic method for monitoring and reporting the electrode status was validated in a one-month-long laboratory test followed by a field test in a stream near an agricultural facility. Moreover, a self-diagnostic index (SDI) was applied in the final field experiments with an accuracy of 0.77.

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Section: Introductionmentioning

confidence: 99%

Water Nitrate Remote Monitoring System with Self-Diagnostic Function for Ion-Selective Electrodes

Park

Kim

et al. 2021

Sensors

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“…As a drinking water standard, ORP value takes into account varieties of chemical elements in the water, which is easy to display the water quality with electronic instruments. According to the Environmental Protection Agency (EPA), the ORP of drinking water should be approaching 250 mV [13]. ORP is an electrochemical parameter and the principle of an ORP electrode is not obscure.…”

Section: Introductionmentioning

confidence: 99%

A MEMS-Based Multi-Parameter Integrated Chip and Its Portable System for Water Quality Detection

Wang

Bian

et al. 2020

Micromachines

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As an important means to protect water resources, water quality detection is of great social and economic significance. Water quality detection sensors processed by micro-electro-mechanical system (MEMS) technology have the advantages of low-cost, small size, and high sensitivity. In this paper, a multi-parameter water quality detection integrated sensor chip is further studied, and a portable detection system using this chip is developed. Temperature, pH, oxidation-reduction potential (ORP), conductivity and concentration of copper ions (Cu2+) are selected as typical water quality parameters. Experiments of sensor calibrations using this portable detection system were performed in standard solutions. The sensor has a sensitivity of −57.34 mV/pH in pH detection and 5.95 Ω/°C in temperature response. ORP is directly detected by Pt microelectrode on the chip and the relative error is less than 3%. The electrode constant of the sensor is 1.416 cm−1 and the linearity is 0.9995 in conductivity detection. With the gold nanoparticles deposited on the electrode, the detection peak of Cu2+ appears at 280 mV and the sensor shows good linearity to the concentration of Cu2+ in the range of 0–0.6 mg/L. The detection limit of Cu2+ concentration is 2.33 μg/L. Through measurement and calculation, the accuracy of the portable system is within 4%. This portable multi-parameter water quality detection system with the MEMS-based integrated chip shows great potential in the field and fast detection.

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“…These new possibilities are viable due to invested efforts in development and integration of sensor, actuation and microfluidics technologies. Sensing technologies in the microfluidic environment are numerous [2,3,4,5,6,7,8,9,10] and most often present optical [7,8] or electrical [3,4] signal at the output of a measurement transducer. In particular, every sensing technology has its advantages and disadvantages, with respect to price, size, integration capability, multi-functionality, need for labels, fabrication methods, and many other [10,11].…”

Section: Introductionmentioning

confidence: 99%

An Interdigital Capacitor for Microwave Heating at 25 GHz and Wideband Dielectric Sensing of nL Volumes in Continuous Microfluidics

Markovic

Bao

Maenhout

et al. 2019

Sensors

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This paper proposes a miniature microwave-microfluidic chip based on continuous microfluidics and a miniature interdigital capacitor (IDC). The novel chip consists of three individually accessible heaters, three platinum temperature sensors and two liquid cooling and mixing zones. The IDC is designed to achieve localized, fast and uniform heating of nanoliter volumes flowing through the microfluidic channel. The heating performance of the IDC located on the novel chip was evaluated using a fluorescent dye (Rhodamine B) diluted in demineralized water on a novel microwave-optical-fluidic (MOF) measurement setup. The MOF setup allows simultaneous microwave excitation of the IDC by means of a custom-made printed circuit board (connected to microwave equipment) placed in a top stage of a microscope, manipulation of liquid flowing through the channel located over the IDC with a pump and optical inspection of the same liquid flowing over the IDC using a fast camera, a light source and the microscope. The designed IDC brings a liquid volume of around 1.2 nL from room temperature to 100 °C in 21 ms with 1.58 W at 25 GHz. Next to the heating capability, the designed IDC can dielectrically sense the flowing liquid. Liquid sensing was evaluated on different concentration of water-isopropanol mixtures, and a reflection coefficient magnitude change of 6 dB was recorded around 8.1 GHz, while the minimum of the reflection coefficient magnitude shifted in the same frequency range for 60 MHz.

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Multifunctional Water Sensors for pH, ORP, and Conductivity Using Only Microfabricated Platinum Electrodes

Cited by 24 publications

References 29 publications

Water Nitrate Remote Monitoring System with Self-Diagnostic Function for Ion-Selective Electrodes

Water Nitrate Remote Monitoring System with Self-Diagnostic Function for Ion-Selective Electrodes

A MEMS-Based Multi-Parameter Integrated Chip and Its Portable System for Water Quality Detection

An Interdigital Capacitor for Microwave Heating at 25 GHz and Wideband Dielectric Sensing of nL Volumes in Continuous Microfluidics

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