Visual Colorimetry for Trace Antimony(V) by Ion-Pair Solid-Phase Extraction with Bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III) on a PTFE Type Membrane Filter

Abstract

A new visual colorimetry for trace antimony(V) based on ion-pair solid-phase extraction to a PTFE-type membrane filter with bis[2-(5-chloro-2-pyridylazo)-5-diethylaminophenolato]cobalt(III) ion ([Co(5-Cl-PADAP)2] + ) has been developed. Experiments showed that hexachloroantimonate(V) ion (SbCl6 -) was adsorbed with [Co(5-Cl-PADAP)2] + to the front surface of the PTFE filter. The adsorption of antimony(V) ion was promoted by the addition of lithium chloride as a source of chloride ion. The excess reagent of [Co(5-Cl-PADAP)2] + was eluted by rinsing with a 10 wt% methanol aqueous solution. In this case, the slow rate of the hydrolysis reaction of SbCl6 -and the difference of the hydrophobicity of the ion pairs were important for adsorption and separation with a PTFE-type membrane filter. The antimony(V) concentration was determined through a visual comparison with a standard series. The visual detection limit was 0.10 μg. The calibration curve assessed with the reflection spectrometric responses at 580 nm was linear in the concentration range of 0.10 -1.2 μg (r = 0.996). The proposed method has been applied to the determination of sub-microgram levels of antimony(V) ion in water samples.

Sensitive Silver-Enhanced Microplate Apta-Enzyme Assay of Sb3+ Ions in Drinking and Natural Waters

“…Currently, colorimetric methods deserve special attention as they offer a visual assessment of color change, allowing an easy readout of analytical signals. Colorimetric techniques for Sb 3+ detection using indicator dyes [14][15][16] and nanoparticles [17][18][19] were developed. The application of dyes such as bis [2-(5-chloro-2-pyridylazo)-5-diethylaminophenola to]cobalt(III), bromopyrogallol red and pyrene causes the formation of complexes with Sb 3+ and is followed by photo-or fluorometric detection.…”

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

“…[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.…”

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

“…[1][2][3][4][5][6][7][8][9][10][11][12][13] Solid-phase spectrometry based on simple comparison of the coloration of the membrane filters provides highly sensitive determination because of a concentration of the target analyte into extremely small volumes. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] In these cases, the recovery of the analytes tends to improve as the pore size of the filters decreases. However, small pore sizes cause an increase of the backpressure during filtration, which often results in prolonged pretreatment times.…”