3.1 Flow injection analysis

Flow injection analysis is a technique to detect the flowing analyte in an appropriate device where carries a zone of sample toward the surface of working electrode. It simply divided two types of flowing, wall jet and flow through, which the flow direction is perpendicular or parallel to the electrode. (see Figure 1,2) The design of flow cell must be satisfied with the high signal to noise ratio, low dead volume, high mass transfer rate, well defined hydrodynamics, small ohmic drop, and ease of construction and maintenance.(1) The attractive solution is to develop a flow cell for disposable screen printed electrode or a disposable lab-on-chip.

• 3.1.1 An electrochemical cell coupled with disposable screen electrodes for use in flow injection analysis

  
  An electrochemical coupled with disposable screen printed electrodes (SPEs) that is specifically designed for flow injection analysis (FIA) is illustrated as shown in Figure 3. The cell is made of foldable polyoxymethylene thick platelets with the bottom portion consisting of a cavity track to drag the SPEs in position and the top portion having predrilled T like holes to arrange the Ag/AgCl reference electrode and stainless steel inlet and outlet. An O ring is suitably fixed on the top of the working electrode to form a thin layer space where the electrochemical reaction can take place.



• 3.1.2 Selective Determination of Arbutin in Cosmetic Products Through Online Derivatization Followed by Disposable Electrochemical Sensor

  
  The integration of a ColeParmer microprocessor pump drive and a manual injector with Zensor SF-100 thin-layer detecting electrochemical cell was successfully achieved for the determination of arbutin (AR) in cosmetic products. The sample of arbutin was pumped through the MnO2 reactor to be oxidized, and then the oxidized AR flowed toward the screen printed carbon electrode to undergo the electrochemically reduced reaction. (see Figure 4) The resulting signal was obtained with the amperometric method as shown in Figure 5.
  



• 3.1.3 Simultaneous detection of NADH and H2O2 using flow injection analysis based on a bifunctional poly(thionine)-modified electrode

  
  Simultaneous detection of NADH and H2O2 has been successfully developed based on bifunctional poly(thionine)-modified screen printed carbon electrode with flow injection analysis. It is designed a poly(thionine)-modified ring disk electrode for detection of NADH at disk electrode and H2O2 at ring electrode with good sensitivity and limit of detection by using Zensor SF100 flow cell system.
  

• 3.1.4 Determination of Thioglycolic Acid in Hair-Waving Products by Disposable Electrochemical Sensor Coupled with High-Performance Liquid Chromatography

  
  It is available to integrate the Zensor SF100 flow cell with high performance chromatography (HPLC) and disposable screen printed electrode to determine the thioglycolic acid (TGA) in commercial hair-waving products. The flow injection analysis (FIA) and LC experiments were performed with a Beckman 126 pump and a sample introduction channel auto-sampler with an injection loop of 20 μL. (see Figure 8) The high performance liquid chromatogram of TGA samples was analyzed as illustrated in Figure 9.
  
  

Reference

Please click the link below

• 1.Jyh-Myng Zen, Hsueh-Hui Yang, Mei-Hsin Chiu, Chao-Hsun, Ying Shih, Journal of AOA C International Vol. 94, N o. 3, 2011
• 2. Jyh-Myng Zen,Hsueh-Hui Yang,Mei-Hsin Chiu, Yu-Ju Chen, Ying Shih, JOURNAL OF AOAC INTERNATIONAL VOL. 92, NO. 2, 2009
• 3.Allen J. Bard, Larry R. Faulkner, Electrochemical Methods and Applications 2nd, 2001