Sequential Injection Analysis of Thiocyanate Ions Using a Microfluidic Polymer Chip with an Embedded Ion-Selective Electrode

Abstract

A sequential injection analysis (SIA) system for the determination of SCN -ion using a microfluidic polymer chip with an embedded SCN -ion-selective electrode (SCN --ISE) as a detector was developed. Under the optimal flow conditions of the SIA system, the SCN --ISE showed a good linear relationship between peak heights and logarithmic concentrations of SCN -ion with a Nernstian slope of 59.4 ± 3.8 mV decade -1 in a concentration range from 1.0 × 10 -5 to 1.0 × 10 -1 mol dm -3 . Sample throughput of the present system for the determination of SCN -ion was approximately 12 samples h -1. The proposed SIA system was applied to the determination of the level of SCN -ion in human saliva samples.

A New Microfluidic Polymer Chip with an Embedded Cationic Surfactant Ion-selective Optode as a Detector for the Determination of Cationic Surfactants

“…7,11,12,[14][15][16][17] Next, part B, part C and part D (C is the middle) were sandwiched between two glass plates and pressed by a double clip, and put into an oven at 110 C for 30 min for thermal fusion of parts B, C and D (part E0). A hole was drilled using a 1.05 mm driller at 0.5 cm length and 1 cm width of both sides of part E0 for fabricating a channel of a sample solution and waste (part E).…”

“…[7][8][9][10][11][12][13][14][15][16][17] Among electrochemical detection methods, an ion-selective electrode (ISE) and an ion-sensitive field effect transistor (ISFET) are effective as detection methods of a microfluidic chip. This is because ISE and ISFET are easy to miniaturize and can easily be fabricated at low cost, and the sensitivity of ISE and ISFET does not decrease, even if their size is reduced.…”

“…This is because ISE and ISFET are easy to miniaturize and can easily be fabricated at low cost, and the sensitivity of ISE and ISFET does not decrease, even if their size is reduced. [10][11][12][13][14][15][16][17] We have already developed a new microfluidic polymer chip with an embedded ISE, where a channel on the chip was prepared by using a small-diameter wire as a template of the channel. 11,12,[14][15][16][17] On the other hand, ion-selective optical sensor (Optode) membranes are suited for a detector of microfluidic chips, compared with the ISE and the ISFET.…”

“…[10][11][12][13][14][15][16][17] We have already developed a new microfluidic polymer chip with an embedded ISE, where a channel on the chip was prepared by using a small-diameter wire as a template of the channel. 11,12,[14][15][16][17] On the other hand, ion-selective optical sensor (Optode) membranes are suited for a detector of microfluidic chips, compared with the ISE and the ISFET. [18][19][20][21][22][23][24] From the viewpoints of applications to microfluidic technology, optodes are superior to ISEs because they are not subject to electrical noise, and no contacts to microfluidic chips are required for measurements.…”

Sequential Injection Analysis of Anionic Surfactants Using On-line Preconcentration Technique and a Microfluidic Polymer Chip with an Embedded Ion-Selective Electrode as a Detector

“…[33][34][35] Recently, ISEs have been often used as a detector of SIA. [36][37][38][39][40][41][42][43] An ideal automated analytical method for the determination of ASs will be developed using a combination of advantages of the SIA system and microfluidic chips with embedded miniaturized ISEs. Generally, AS in environmental water samples is not determined using AS-ISEs because lower limit of Nernstian response of reported AS-ISEs is order of approximately 10…”