All-in-One Flow Injection Spectrophotometric System for Field Testing

Abstract

To date one of the most significant innovative trends in chemical analysis is to develop analytical instruments that have processed to analyze on-site. Such an apparatus should minimize problems related to sample transports, sample handlings and sample storages. Currently, a traditional wet analysis in laboratories has been replaced with a portable device designed to minimize problems from sending samples to the lab. One of the practical chemical methods which can be developed as the mobile device is flow injection analysis (FIA) because the scaled-down FIA manifolds have been already presented. Regarding the detection, the rapid progress in material science and electronic technology consents the construction of portable detection devices, particularly light-emitting-diodes (LEDs) based-spectrometers. In this work, the FIA analyzer integrated with a built-in detector was designed for on-site chemical testing. A double syringes pump was assembled for transporting of the reagent carrier which were merged at the first mixing coil. A plug of a sample solution was inserted automatically by using a six-port-valve and was mixed with the carrier stream at the second mixing coil before directed to the detector. The heart of the developed analyzer is the built-in spectrophotometric sensor, made of the LEDs as a light source and a photodiode as a detector. The continuous stream of the final product was pushed into a quartz flow-through cuvette and then was exposed to the LED light. Finally, the absorbance of the product solution was calculated according to the Beer-Lambert law.