A novel approach for the determination of Al3+ from aqueous samples was developed using an optode membrane produced by physical inclusion of Al3+ selective reagent, which is morin into a plasticized poly(vinyl chloride). The inclusion of Triton X-100 was found to be valuable and useful for enhancing the sorption of Al3+ ions from liquid phase into the membrane phase, thus increasing the intensity of optode's absorption. The optode showed a linear increase in the absorbance at lambda(max)= 425 nm over the concentration range of 1.85 x 10(-6)-1.1 x 10(-4) mol L-1 (0.05-3 mu g mL(-1)) of Al3+ ions in aqueous solution after 5 min. The limit of detection was determined to be 1.04 x 10(-6) mol L-1 (0.028 mu g mL(-1)). The optode developed in the present work was easily prepared and found to be stable, has good mechanical strength, sensitive and reusable. In addition, the optode was tested for Al3+ determination in lake water, river water and pharmaceutical samples, which the result was satisfactory. (C) 2015 Elsevier B.V. All rights reserved.

The effect of surfactants on the Al(III)-morin complex have been studied. It was found that non-ionic surfactant noticeably enhances the absorbance of the Al(III)-morin complex. Determination of submicrogram quantities of Al(III) ion at pH4.00 was made possible by the addition of triton X-100. Maximum absorption was obtained at wavelength of 425 nm, with the calculated molar absorptivity, epsilon e, of 9.31 x 10(3) l. mol(-1). cm(-1). A linear calibration curve of 0.03 to 2.0 mu g mL(-1) with the detection limit of 0.015 mu g mL(-1) was attained for determination of Al(III) ion. The calculated relative standard deviation (r.s.d) was 2.2% for Al(III) ion quantified at 1.0 mu g mL(-1). The influence of foreign ions towards the Al(III)-morin complex responses have been carried out too, with Cu(II), Zn(II) and Pb(III) were found to be the main interferences.

This paper reports the use of a polymer inclusion membranes (PIMs) for direct determination of Al(III) ions in natural water by using a fluorescence based optode. The best composition of the PIMs consisted of 60 wt.% (m/m) poly (vinyl chloride) (PVC) as the base polymer, 20 wt.% (m/m) triton X-100 as an extractant, 20 wt.% (m/m) dioctyl phthalate (DOP) as plasticizer and morin as the reagent, was used in this study. The inclusion of triton X-100 was used for enhancing the sorption of Al(III) ions from liquid phase into the membrane phase, thus increasing the optode fluorescence intensity. The optimized optode was characterized by a linear calibration curve in the range from 7.41 x 10(-7) to 1.00 x 10(-4) molL(-1) of Al(III), with a detection limit of 5.19 x 10(-7) molL(-1). The response of the optode was 4 min and reproducible results were obtained for eight different membranes demonstrated good membrane stability. The optode was applied to the determination of Al(III) in natural water samples. The result obtained is comparable to atomic absorption spectrometry method.

A highly sensitive and simple reagent immobilization procedure for a non-plasticized fluorescence optode based on polymer inclusion membranes (PIM) has been developed. The preparation procedure is based on physical immobilization procedure, namely encapsulation technique which produces an optical sensing membrane. The sensitive PIM contains poly (vinyl chloride) (PVC) as the base polymer, Aliquat 336 as an extractant and sodium morin-5-sulphonate (NaMSA) as the reagent. The use of PIM has increased the response of the PIM based optode about five-fold enhancement compared to the non-PIM optode. The optimized optode was characterized by a linear calibration curve in the range from 5.19 x 10(-7) to 6.00 x 10(-5) mol L-1 of aluminium(III) (Al(III)), with a detection limit of 4.07 x 10-7 mol L-1. The response of the optode was three minutes and it was also found to be reproducible. The optode has been successfully tested for the determination of Al(III) in natural water samples and result obtained is comparable to atomic absorption spectrometry method. (C) 2014 Elsevier B.V. All rights reserved.

An optical Al(III) sensor base on reflectance principle has been developed using polymer inclusion membranes (PIMs) beads. The immobilized PIMs beads are consists of poly(vinyl chloride) (PVC), Aliquat 336, dioctyl phthalate (DOP) and eriochrome cyanine R (ECR) reagent. The sensor which was based on immobilized PIMs beads produced higher response compared to sensor based on non-immobilized PIMs beads. The response time of the sensor was 3 min with an optimum pH value of 6.0. This optical Al(III) sensor gave a linear response at the range of 5.56x10(-5) - 3.52x10(-4) molL(-1), with the limit of detection value 3.41x10(-5) molL(-1). Validation of Al(III) value in spiked natural water samples by using Al(III) sensor developed in this study showed no significance differences compared with results obtained by using conventional atomic absorption spectrophotometer.