An Environmentally Friendly Compact Microfluidic Hydrodynamic Sequential Injection System Using Curcuma putii Maknoi & Jenjitt. Extract as a Natural Reagent for Colorimetric Determination of Total Iron in Water Samples

Abstract

The miniaturization of analytical systems and the utilization of nontoxic natural extract from plants play significant roles for green analytical chemistry methodology. In this work, the microfluidic hydrodynamic sequential injection (HSI) with the LED-phototransistor colorimetric detection system has been proposed to create an ecofriendly and low-cost miniaturized analytical system for online determination of iron in water samples using Curcuma putii Maknoi & Jenjitt. extracts as high stability and good selectivity of a natural reagent. The proposed method was designed for online solution mixing and colorimetric detection on a microfluidic platform. The Curcuma putii Maknoi & Jenjitt. extracts and standard/samples were sequentially aspirated to fill the channel before entering the built-in flow cell. The intensity of iron-Curcuma putii Maknoi & Jenjitt. extract complex was monitored under the optimum conditions of flow rate, sample volume, mixing zone length, and aspiration sequences, by altering the gain control of the colorimetric detector to achieve good sensitivity. The results demonstrated a good performance of the green analytical systems. A linear calibration graph in the range of 0.5–6.0 mg L−1 was obtained with a limit of detection at an adequate level of 0.11 mg L−1 for water samples with a sample throughput of 30 h−1. The precise and accurate measurement results were achieved with relative standard deviations in the range of 1.61–1.72%, and percent recoveries were found in the range of 90.6–113.4. The proposed method offers cost-effective, easy operation over an appropriate analysis time (2 min/injection) with good sensitivity and is environmentally friendly with low consumption of solutions and the use of high stability and good selectivity of nontoxic reagents. The achieved method was demonstrated to be a good choice for routine analysis.

Speciation of Iron Using Desferal via Simple pH Change and a Single Calibration Curve: High-Throughput Optical Sensor Based on 96-Well Plates and an Overhead Book Scanner as Detector

“…The speciation of iron (Fe(II)/Fe(III)) is quite important in numerous fields such as plant science, the environment, pharmaceutics, and biology, and an interested reader can find several applications in the international literature [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. A screening of the recently published methods (2016 to date) revealed that the speciation of iron (and/or the determination of total iron) is based on more or less known red/ox pretreatment steps, followed by state-specific color-forming or fluorescent reactions.…”

“…An overview of the principles of such procedures can be found in Table 1. As can be seen from the methods included in Table 1, they can be categorized into three main groups: (i) methods that are based on the reduction of Fe(III), typically by ascorbic acid or hydroxylamine [9,10,[12][13][14][15]17,19,20,24]; (ii) methods that are based on the oxidation of Fe(II) by H 2 O 2 [11,16,18]; and (iii) methods where both Fe(II) and Fe(III) interact with the selected probe, offering the possibility to perform total iron quantification in a single run (no speciation is reported though) [21][22][23]. Alternatively, a less-applied recent procedure is the column-based separation of Fe(II)/Fe(III) using cation exchange chromatography followed by compatible ICP detection [25].…”