ABSTRACT
In this work, a high integrated water detection system comprised a miniaturized and high precision homemade colorimeter, a microfluidic analysis module and a wireless module was reported. A reagent reaction based on the ammonium molybdate spectrophotometric method was recorded for the estimation of phosphate in natural water. A laser self-modulating module of 880â¯nm was used as the radiation source. A microfluidic chip was employed to fit the colorimeter with an optimized micro flow path for low liquid consumption and high precision detection. The wireless module consisted of two parts, using ZigBee and GSM modules to realize short and remote displaying and controlling. Applying a novel optimized algorithm, a wide linear response was obtained ranging from 0.02 up to 9.5â¯mgâ¯L-1. The optimization of colorimeterare mainly in the core detection part, allowing an improvement of the detection limit, achieving a result of 0.009â¯mgâ¯L-1. A low reagent consumption of 0.004â¯mg ascorbic acid and 0.011â¯mg ammonium molybdate for per determination was attained. Experimental results have also shown that the system could maintain good stability among broad room temperature changing from 17⯰C to 35⯰C with less energy consumption. The miniaturized colorimeter-based water detection system opens new avenue for operating in remote distance to get high precision measurements of phosphate in natural water.
ABSTRACT
Water quality detection plays an increasingly important role in environmental protection. In this work, a novel colorimeter based on the Beer-Lambert law was designed for chemical element detection in water with high precision and miniaturized structure. As an example, the colorimeter can detect phosphorus, which was accomplished in this article to evaluate the performance. Simultaneously, a modified algorithm was applied to extend the linear measurable range. The colorimeter encompassed a near infrared laser source, a microflow cell based on microfluidic technology and a light-sensitive detector, then Micro-Electro-Mechanical System (MEMS) processing technology was used to form a stable integrated structure. Experiments were performed based on the ammonium molybdate spectrophotometric method, including the preparation of phosphorus standard solution, reducing agent, chromogenic agent and color reaction. The device can obtain a wide linear response range (0.05 mg/L up to 7.60 mg/L), a wide reliable measuring range up to 10.16 mg/L after using a novel algorithm, and a low limit of detection (0.02 mg/L). The size of flow cell in this design is 18 mm × 2.0 mm × 800 µm, obtaining a low reagent consumption of 0.004 mg ascorbic acid and 0.011 mg ammonium molybdate per determination. Achieving these advantages of miniaturized volume, high precision and low cost, the design can also be used in automated in situ detection.
ABSTRACT
Traditional sound sources and sound detectors are usually independent and discrete in the human hearing range. To minimize the device size and integrate it with wearable electronics, there is an urgent requirement of realizing the functional integration of generating and detecting sound in a single device. Here we show an intelligent laser-induced graphene artificial throat, which can not only generate sound but also detect sound in a single device. More importantly, the intelligent artificial throat will significantly assist for the disabled, because the simple throat vibrations such as hum, cough and scream with different intensity or frequency from a mute person can be detected and converted into controllable sounds. Furthermore, the laser-induced graphene artificial throat has the advantage of one-step fabrication, high efficiency, excellent flexibility and low cost, and it will open practical applications in voice control, wearable electronics and many other areas.
