TY - JOUR
T1 - Integrated FIA for the determination of ascorbic acid and dehydroascorbic acid in a microafabricated glass-channel by thermal-lens microscopy
AU - Sorouraddin, Hussein M.
AU - Hibara, Akihide
AU - Proskurnin, Mikhail A.
AU - Kitamori, Takehiko
PY - 2000
Y1 - 2000
N2 - An on-chip chemical micro-determination device, integrating the FIA system, was applied to L-ascorbic acid (AA) and dehydroascorbic acid (DHAA) determination. Microchannels having a 250x100 μm cross-section were fabricated in a quarts glass chip as a component in an integrated FIA system. They were put to use for flow, mixing, reaction, and detection. The reaction system was a coupled redox-complexation reaction between AA and a 1,10-phenantroline-Fe(III) mixture. Sample solutions were introduced into micro-channels by micro-syringes, the flow rate was controlled by a micro-syringe pump, and the reagents, were mixed by molecular diffusion. A photothermal microscope was used for the ultra-sensitive detection of the non-fluorescent reaction product (ferroin). For DHAA determination, dithiothreithol was used as a reducing agent and the total AA was determined. The DHAA quantity was calculated by subtraction. This method allows for the determination of AA with a linear range of up to 40 μM. The RSD for 25 μM AA (n=5) is 1%, and the limit of detection (LOD) is 0.1 μM. The procedure was successfully applied to determining the AA and DHAA content of urine and AA in vitamin C tablets. The results agree well with those obtained by reference methods.
AB - An on-chip chemical micro-determination device, integrating the FIA system, was applied to L-ascorbic acid (AA) and dehydroascorbic acid (DHAA) determination. Microchannels having a 250x100 μm cross-section were fabricated in a quarts glass chip as a component in an integrated FIA system. They were put to use for flow, mixing, reaction, and detection. The reaction system was a coupled redox-complexation reaction between AA and a 1,10-phenantroline-Fe(III) mixture. Sample solutions were introduced into micro-channels by micro-syringes, the flow rate was controlled by a micro-syringe pump, and the reagents, were mixed by molecular diffusion. A photothermal microscope was used for the ultra-sensitive detection of the non-fluorescent reaction product (ferroin). For DHAA determination, dithiothreithol was used as a reducing agent and the total AA was determined. The DHAA quantity was calculated by subtraction. This method allows for the determination of AA with a linear range of up to 40 μM. The RSD for 25 μM AA (n=5) is 1%, and the limit of detection (LOD) is 0.1 μM. The procedure was successfully applied to determining the AA and DHAA content of urine and AA in vitamin C tablets. The results agree well with those obtained by reference methods.
UR - http://www.scopus.com/inward/record.url?scp=0033755807&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033755807&partnerID=8YFLogxK
U2 - 10.2116/analsci.16.1033
DO - 10.2116/analsci.16.1033
M3 - Article
AN - SCOPUS:0033755807
VL - 16
SP - 1033
EP - 1037
JO - Analytical Sciences
JF - Analytical Sciences
SN - 0910-6340
IS - 10
ER -