The use of a polymer inclusion membrane in a paper-based sensor for the selective determination of Cu(II).
A disposable paper-based sensor (PBS) is described for the determination of Cu(II) in natural and waste waters at approximately 2 cents per measurement. The device makes use of a polymer inclusion membrane (PIM) to provide the selectivity for Cu(II). The PIM consists of 40 wt% di(2-ethlyhexyl) phosphoric acid (D2EHPA) as the carrier, 10 wt% dioctyl phthalate (DOP) as a plasticizer, 49.5 wt% poly(vinyl chloride) (PVC) as the base polymer and 0.5 wt% (mm(-1)) 1-(2'-pyridylazo)-2-naphthol (PAN) as the colourimetric reagent. High selectivity under mildly acidic conditions (HCl, pH 2.0) is achieved for Cu(II) in the presence of frequently encountered metal ions in natural and waste waters such as Fe(III), Al(III), Zn(II), Cd(II), Pb(II), Ca(II), Mg(II), and Ni(II). The laminated PBS consists of a PIM sensing disc (2mm in diameter) attached to the centre of a circular hydrophilic zone (7 mm in diameter) pretreated with 0.01 M HCl. This hydrophilic zone separates the sample port (a circular hole in the plastic cover) from the PIM sensing disc. After introducing 19.2 μL of a sample/standard solution to the sample port, Cu(II) diffuses across the hydrophilic zone and is extracted into the PIM disc as the Cu(II)-D2EHPA complex which subsequently reacts with PAN to produce the red-purple coloured Cu(II)-PAN complex. The colour intensity of the PIM disc is measured 15 min after sample/standard introduction by scanning using a flatbed scanner. Under optimal conditions the device is characterized by a limit of detection (LOD) and limit of quantitation (LOQ) of 0.06 and 0.21 mg L(-1) Cu(II), respectively, with two linear ranges together covering the Cu(II) concentration range from 0.1 to 30.0 mg L(-1). The PBS was successfully applied to the determination of Cu(II) in hot tap water and mine tailings water.
School of Chemistry, The University of Melbourne, Victoria 3010, Australia; Centre for Aquatic Pollution Identification and Management (CAPIM), The University of Melbourne, Victoria 3010, Australia.
B Manori
BM
Jayawardane
Lilibeth dlC
Ld
Coo
Robert W
RW
Cattrall
Spas D
SD
Kolev
D002413:Cations, Divalent / Q000032:analysis; D003300:Copper / Q000032:analysis*; D004784:Environmental Monitoring / Q000295:instrumentation*; D004867:Equipment Design; D057230:Limit of Detection; D008567:Membranes, Artificial; D009284:Naphthols / Q000737:chemistry; D010209:Paper; D010756:Phosphoric Acids / Q000737:chemistry; D010795:Phthalic Acids / Q000737:chemistry; D011143:Polyvinyl Chloride / Q000737:chemistry; D014867:Water / Q000032:analysis*
D002413:Cations, Divalent; D008567:Membranes, Artificial; D009284:Naphthols; D010756:Phosphoric Acids; D010795:Phthalic Acids; D014867:Water; C032279:phthalic acid; D003300:Copper; D011143:Polyvinyl Chloride; C030242:phosphoric acid; C028405:2-naphthol
1-(2-Pyridylazo)-2-naphthol (PAN); Detection of Cu(II); Di(2-ethlyhexyl) phosphoric acid (D2EHPA); Paper-based sensor (PBS); Polymer inclusion membrane (PIM)