Utilization of transport efficacy of novel calix[4]arene-embedded polymer inclusion membrane towards trace metals

In this study, 25,27-bis(3-mercaptopropoxyl)-26,28-dihydroxy calix[4]arene was successfully synthesized from the reaction of calix[4]arene-dialkylbromide derivative with thiourea. The structure of 25,27-bis(3-mercaptopropoxyl)-26,28-dihydroxy calix[4]arene was fully characterized using ¹HNMR, ¹³CNMR and elemental analysis techniques. The obtained mercapto-substituted calix[4]arene derivative was employed as an additive material along with cellulose triacetate (CTA) and 2-nitrophenyl octyl ether (o-NPOE) for the preparation of a novel polymer inclusion membrane (C@PIM). The structure and surface morphology of mercapto-substituted calix[4]arene-embedded polymer inclusion membrane was determined using thermogravimetric analysis, scanning electron microscopy and elemental analysis techniques. Donnan dialysis system was also used to assess the transport efficacy of C@PIM towards Pb(II), Zn(II), Cu(II), Ni(II), Cd(II) and Co(II) ions. The results show that new C@PIM exhibited 99% transport efficacy but also selectivity toward Ni(II) and other ions.     

A Rapid Spectrophotometric Method to Resolve Ternary Mixtures of Propyphenazone, Caffeine, and Acetaminophen in Tablets

Summary.  A simple and rapid derivative spectrophotometric assay procedure is described for the analysis of caffeine (1), acetaminophen (2), and propyphenazone (3) in tablet formulations. The concentration range of application is 5.0–25.0 μg·cm⁻³ for 2 and 3 and 1.0–5.0 μg·cm⁻³ for 1. The method involves the extraction of the drugs from tablets with 0.1 N H₂SO₄, filtration, appropriate dilution, and measurement of the fourth derivative absorbance values at zero crossing wavelengths of 230.0, 263.2, and 256.6 nm for 1, 2, and 3. As a reference method, a reversed phase HPLC procedure was developed. Commercially available tablets were analyzed; statistical comparison of the results with those obtained from the reference method showed good agreement. The derivative spectrophotometric method has the advantage of being simple, rapid, inexpensive, and easy to perform. Received April 18, 2001. Accepted (revised) June 5, 2001