Passive micromixer integration with a microfluidic chip for calcium assay based on the arsenazo III method

Abstract

The ability for low reagent consumption and minimum waste production in a miniaturised system has generated great interest in the green chemistry field. Herein, a microfluidic system for calcium assays using the arsenazo III method has been developed. The reaction between arsenazo III and calcium to form a blue-purple coloured complex is measured by an embedded miniature fibre optic spectrometer through absorbance increments at 650 nm. A linear range was obtained from 0.2 to 3 mg dL -1 with a detection limit of 0.138 mg dL -1 (S/N=3). The method exhibited good reproducibility based on low and high calcium tests with control serums, the within-run coefficient of variation (CVs) (4.10% and 3.91%), and the run-to-run CV (4.6%) were obtained. The carry-over effect of the method was also 1.98%, which is acceptable for the current system. When compared to a conventional spectrophotometric method, this portable, microfluidic method correlated highly when evaluating serum samples (r 2 =0.985; n=15). This similarity suggests that our proposed system could be used for determining the amount of calcium in serum samples.

Simple Spectrophotometric Sequential Injection Analysis System for Determination of Serum Calcium

“…Based on the o-cresolphthalein complexone-based SIA approach, their detection limit is maximised at 0.125 mM. However, the SIA method described here is less sensitive than our previous microfluidic-based technique [5]. Nevertheless, the SIA method was more advantageous than the microfluidic platform, in terms of high throughput analysis.…”

“…Currently, numerous approaches for quantifying the amount of calcium based on arsenazo III have been reported, such as the spectrophotometric method [3,4], microfluidic-based platforms [5][6][7], flow injection analysis [8][9][10], and sequential injection analysis (SIA) [11,12]. The preceding studies on the determination of calcium by means of SIA system have been applied and validated, but solely for the environmental samples, no utility being expressed for the complex biological samples.…”

Automated passive serial dilution microfluidic chip for calcium quantification based on the Arsenazo III method

“…The capacity for absolute control over geometry, high repeatability, fast reaction times, and reduced consumption of expensive reagents in microfluidic system can facilitate multiple tests on the same POC platform and render the system cost-effective, portable, and efficient. [7][8][9] Various microfluidic chips have been presented in the literature for performing the sample preparation step in urinalysis 10,11 for the detection and measurement of glucose, 12 urinary proteins, [13][14][15] hormones, 16 biomarkers for cancers, 17 leukocytes, 18 nitrate, urinary ketones and electrolytes. 19,20 The primary requirement for such a microfluidic system is maintaining precise mixing of calibrants in a specific ratio.…”

CO2 laser ablation of microchannel on PMMA substrate for Koch fractal micromixer

“…The manufacture of micromixers with polymer materials is a major trend in the development of micromixing technology; it is an important part of microfluidic chip [14]. Polymethyl methacrylate (PMMA) is a major thermoplastic polymer that is widely used as a substrate material for manufacturing a micromixer [15].…”