On-site Visual Colorimetry for Dissolved Trace Manganese after Extraction into Ion-Associate Phase Retained on Membrane Filter

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.…”

Visual colorimetry for determination of trace arsenic in groundwater based on improved molybdenum blue spectrophotometry

“…Solid phase extraction of colored species on an MF has been applied to visual colorimetry of phosphate nickel, antimony(V), chromium(VI), manganese, formaldehyde and urinary protein. [15][16][17][18][19][20][21] These methods are based on the collection of colored species through the affinity to MF materials and a comparison of the MF color with standard colors.…”