On-site Determination of Trace Arsenic by Reflection-Absorption Colorimetry of Molybdenum Blue Collected on a Membrane Filter

Abstract

An on-site determination method for trace arsenic has been developed by collecting it as molybdenum blue (MB) in the presence of tetradecyldimethylbenzylammonium chloride on a mixed cellulose ester membrane filter and by measuring reflection absorbance (RA) of MB on the filter using a laboratory-made palm-top size reflection-absorbance colorimeter with a red light-emitting diode. The value of RA was proportional to the amount of arsenic up to 0.5 μg with a detection limit of 0.01 μg. The proposed method was successfully applied to soil extract and hot-spring water samples.

Droplet-counting Microtitration System for Precise On-site Analysis

“…This system consisted of a commercial battery-driven stirrer IS-M02 (Ikeda Scientific) (9 and 10 in Fig. 1), a laboratory-made microburette (assembly of parts 1,2 and 4 -6), and its stand (3). A rubber dropper bulb (1) had a hole on the top.…”

“…1 Miniaturized apparatuses are portable, and therefore they are useful for in-situ and on-site measurements evolving environmental monitoring. 2,3 A microburette (0.1 mL) with a graduated glass tube and a screw-driven plunger was used for the titration of alkalinity, chloride and dissolved oxygen with errors of less than 1%. 4 A micropipette connected to a micrometer-driven plunger was purchased from Gilmont Instruments, Co.…”

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.…”

Electrogenerated Chemiluminescence of Tris(dibenzoylmethane)phenanthroline Europium(III) as a Light Source: An Application for the Detection of PO43-Based on the Ion Associate Formation of Phosphomolybdic Acid and Malachite Green

“…Several works have been published recently on the use of portable light emitting devices such as LEDs as a light source for the determination of analytes. [12][13][14] We also applied organic photodiodes and LEDs for flow injection analysis, 15,16 and recently, sharp emissions from OLEDs containing an Eu(III) or Tb(III) complex were utilized as a light source for the flow injection determination of phosphate 17 and fluorescent flow injection immunoassay for alkylphenol ethoxylates. 18 So far, we reported the photophysical and ECL properties of several light-emitting materials, whose emission spectra were broad, [19][20][21][22][23] and very recently, we also clarified the ECL behavior of several Eu(III) and Tb(III) complexes composed of N-donor ligands and enolate ions of β-diketonates.…”