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Sensors 2016, 16(8), 1234;

A Miniaturized On-Chip Colorimeter for Detecting NPK Elements

Institute of Microelectronics, Tsinghua University, Beijing 100084, China
Tsinghua National Laboratory for Information Science and Technology (TNList), Tsinghua University, Beijing 100084, China
School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), Sector H-12, Islamabad 44000, Pakistan
Author to whom correspondence should be addressed.
Academic Editor: Simon X. Yang
Received: 7 May 2016 / Revised: 19 July 2016 / Accepted: 2 August 2016 / Published: 4 August 2016
(This article belongs to the Special Issue Sensors for Agriculture)
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Recently, precision agriculture has become a globally attractive topic. As one of the most important factors, the soil nutrients play an important role in estimating the development of precision agriculture. Detecting the content of nitrogen, phosphorus and potassium (NPK) elements more efficiently is one of the key issues. In this paper, a novel chip-level colorimeter was fabricated to detect the NPK elements for the first time. A light source–microchannel photodetector in a sandwich structure was designed to realize on-chip detection. Compared with a commercial colorimeter, all key parts are based on MEMS (Micro-Electro-Mechanical System) technology so that the volume of this on-chip colorimeter can be minimized. Besides, less error and high precision are achieved. The cost of this colorimeter is two orders of magnitude less than that of a commercial one. All these advantages enable a low-cost and high-precision sensing operation in a monitoring network. The colorimeter developed herein has bright prospects for environmental and biological applications. View Full-Text
Keywords: colorimeter; NPK elements; Beer-Lambert’s Law colorimeter; NPK elements; Beer-Lambert’s Law

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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).

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Liu, R.-T.; Tao, L.-Q.; Liu, B.; Tian, X.-G.; Mohammad, M.A.; Yang, Y.; Ren, T.-L. A Miniaturized On-Chip Colorimeter for Detecting NPK Elements. Sensors 2016, 16, 1234.

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