Separation and Simultaneous Determination of Uric Acid and Ascorbic Acid on a Dynamically Modified Poly(dimethylsiloxane) Microchip

Abstract

Poly(dimethylsiloxane) microfluidic channels alternately modified by poly(diallyldimethylammonium chloride) and poly(sodium 4-styrenesulfonate) were successfully used to separate uric acid and ascorbic acid. Results show that uric acid and ascorbic acid can be well separated and detected simultaneously in modified microchips coupled with in-channel electrochemical detection. Under the optimal conditions, the linear ranges of uric acid and ascorbic acid were both from 25 to 600 μM, with the correlation coefficients of 0.997 and 0.996, respectively. The detection limits were 8 μM for uric acid and 5 μM for ascorbic acid. Factors influencing separation and detection, including buffer solution, detection potential and separation voltage, were investigated and optimized. In addition, the dependences of the current response on sensitivity and reproducibility were studied, and the stability of the device was also evaluated in detail. This method was successfully used to determine uric acid and ascorbic acid in human urine.

Electrophoretic Separation of Chlorophenols on Silica Nanospheres-coated Poly(dimethylsiloxane) Microchip Using a Nafion/graphene-modified Carbon Electrode for Detection

“…2, the EOF is more stable against any pH alteration on a modified microchannel other than on a native one. By comparing of the alteration of the EOF values, depending on the pH with reported similar methods [20][21][22][23] ( Table 1), we could find that there was only 0.06 of ΔEOF during a pH change from 8.0 to 11.0, which is the smallest one. Noticeably, there are at least one of two main aspects of difference between our research and those reports.…”

“…Qiu et al 21 reported a poly(diallyldimethylammonium chloride) (PDDA)/poly(sodium-p-styrenesulfonate) (PSS) modified PDMS chip to obtain a stable EOF based on reduced non-specific adsorption. In addition, a PDDA/nano-TiO2 coated microchip and a PDDA/nano-SiO2 coated microchip have also been reported.…”

Chemical modification of PDMS surface without impacting the viscoelasticity: Model systems for a better understanding of elastomer/elastomer adhesion and friction

“…Several other PDMS hydrophilic surface modification strategies have been explored, such as UV treatment [21,22], chemical vapor deposition [23], layer-by-layer (LBL) deposition [24,25], sol-gel coatings [26], silanization [27], dynamic modification with surfactants [28], and protein adsorption [29], but all result in the formation of what can be seen as a bilayer system unstable over time.…”

Simple surface modification of poly(dimethylsiloxane) for DNA hybridization

“…To date, the wettability of PDMS surfaces has been improved by using methods such as plasma treatment, [3][4][5][6] UV treatment, 7,8 chemical vapor deposition, [9][10][11] layer-by-layer ͑LBL͒ deposition, [12][13][14] sol-gel coatings, 15,16 silanization, 17,18 dynamic modification with surfactants, [19][20][21][22] and protein adsorption. [23][24][25] In addition, combinations of UV or plasma treatment with chemical methods such as silanization, [26][27][28] graft polymerization, [29][30][31][32][33][34] and LBL methods 35,36 have been explored.…”