A Rapid Enrichment Technique for the Ultratrace Determination of Nickel in Water Samples Using a Nanofiber-composite Membrane Filter

Abstract

A new method for the rapid enrichment and highly sensitive determination of nickel ion has been developed by using a nanofiber-composite membrane filter, which was fabricated by stacking a nanofibrous material made of nylon 6 over a water-permeable membrane filter. The noncharged nickel-α-furil dioxime complex was adsorbed on a nanofibrous layer of the membrane filter under significantly higher flow rates than those used for conventional solid-phase extraction techniques. Highly sensitive determinations with detection limits at sub-parts per billion levels were achieved by enrichment from 50 mL of the complex solution, and the enrichment was completed within 3 min. The color that was developed on the membrane filter was successfully subjected to visual colorimetric analysis and quantitative determination by solid-phase spectrophotometry. In addition, colorimetric determination was feasible with a handheld spectrometer after elution of the colored agent with 50 μL of acetone. This combination of rapid enrichment and spectrometric measurement in a small-volume sample provides a useful analytical method suitable for on-site analysis, which requires neither expensive instruments nor high laboratory skills.

An Improved Reflection Colorimeter Integrated with a Coaxial Optical-fiber Cable for Highly Sensitive Solid-phase Colorimetry Using a Membrane Filter

“…The preparation of complex solutions is the same as the previous report. 17,25 To a 10-mL aliquot of a sample solution containing nickel(II) ion, 1.0 mL of -FD solution,…”

“…This analytical performance was comparable to the previously reported method using expensive instruments such as a portable spectrophotometer 17 or a densitometer. 25…”

“…[7][8][9][10] This technique, which does not use harmful organic solvents, is suitable for on-site works. A direct comparison of the membrane filter colorations provided by the enrichment onto the filter surface enables highly sensitive determination of the target analyte, [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25] and some methods are commercially available.…”

Polyethylene Terephthalate Nanofiber Sheet as the Novel Extraction Medium for the Determination of Phthalates in Water Samples

“…20,21 A nanofiber-composite membrane filter prepared by a melt spinning method was also reported for the enrichment of nickel in water samples. 22 Phthalates are widely used as plasticizers for increasing the flexibility of polyvinyl chloride (PVC). However, some phthalates are regarded as being endocrine-disrupting compounds.…”

Solid-Phase Extraction for Environmental Analysis

“…Mizuguchi et al reported on a rapid enrichment method for the determination of nickel ion using a nanofiber-composite membrane filter. 9 The enrichment process was completed within 3 min. Hagiwara et al reported the on-site determination of As, Se, and Cr(VI) in drinking-water samples using handheld XRF spectrometry with a Ti-loaded anion-exchange disk SPE.…”