Double-sided Microfluidic Device for Speciation Analysis of Iron in Water Samples: Towards Greener Analytical Chemistry

Abstract

Microfluidics minimize the amounts of reagents and generate less waste. While microdevices are commonly single-sided, producing a substrate with microchannels on multiple surfaces would increase their usefulness. Herein, a polymethymethacrylate substrate incorporating microchannel structures on two sides was sandwiched between two polydimethylsiloxane sheets to create a multi-analysis device, which was used for the spectrophotometric analysis of the ferrous ion (Fe 2+ ) and the ferric ion (Fe 3+ ), by utilizing colorimetric detection. To monitor the signals from both channel networks, dual optical sensors were integrated into the system. The linear ranges for Fe 2+ and Fe 3+ analyses were 0.1 -20 mg L -1 (R 2 = 0.9988) and 1.0 -40 mg L -1 (R 2 = 0.9974), respectively. The detection limits for Fe 2+ and Fe 3+ were 0.1 and 0.5 mg L -1 , respectively. The percent recoveries of Fe 2+ and Fe 3+ were 93.5 -104.3 with an RSD < 8%. The microdevice demonstrated capabilities for simultaneous analysis, low waste generation (7.2 mL h -1 ), and high sample throughput (180 h -1 ), making it ideal for greener analytical chemistry applications.

A Highly Structured 1,10-Phenanthroline Arrayed Hydrophobic Sulfone Membrane Platform for the Rapid Determination and Speciation of Fe2+/Fe3+ Ions in Water

“…Recently, Youngvises et al 19 also demonstrated the rapid determination and speciation of iron on a miniaturized microfluidic setup, but the LOD was in a similar range as of our developed method. Hence, our proposed method overcomes the aforesaid remarks, since it is simple to design, robust and offers good precision, strong selectivity with a good LOD that is lower than the maximum allowable limit (MAL) for iron in water, as reported by WHO.…”

“…The membrane-based sensor may not be as ultrasensitive as other reported methods, 7,8 as shown in Table 2, but it offers a simple one-step procedure with an easy colorimetric readout. Most of the reported methods are multistep 4 that involve complex methodologies, 2,6 or device fabrication 18,19 that require a high-degree of expertise.…”

Do we need Green Analytical Chemistry?

“…19,20 In addition, spectroscopic methods permit real-time process analysis/monitoring in situ/in vivo; and they can be implemented with simple and portable instrumentation while maintaining high selectivity and sensitivity. 21 S2 -Smaller dimensions -Performing measurements on a microchip platform in which functionalised microsystems integrate multiple sample-handling processes (pre-concentration/extraction, chemical/biochemical derivatisation) with the measurement (detection) step substantially reduces the amount of solvents and chemicals. 22 Electrophoretic separation of analytes can easily be included in these miniature systems.…”

Miniaturization of spectrophotometry based on micro flow analysis using norfloxacin as less-toxic reagent for iron determination

“…Besides, Alsuhaimi et al [23] developed microfluidic device for analysis the Fe(II) and Fe(III) by using KSCN and 1,10-phenantroline, respectively. Some other reagents are also used including quercetin [24], morin [24], 7-iodo-8-hydroxyquinoline-5-sulphonic acid [25], 4-aminoantipyrene [26], 2-hydroxyl-5-methyl benzophenone oxime [27], 3-hydroxyl-3-phenyl-l-m-chlorophenyl triazene [28], thioglycolic acid [29] and diformyl hydrazine [30].…”