extraction-spectrophotometric determination of ammonium ion by dibenzo- 18-crown-6 and calmagite

an extraction-spectrophotometric method for the determination of trace amounts of ammonium ion is described. ammonium ion is effectively extracted as a neutral ternary complex nh . db 18c6. calmagite at ph 3.0 into chloroform, followed by spectrophotometric determination at =48 5 nm. molar absorptivity of the ternary complex at this wavelength is 1.08 10 mol cm . beer's law is obeyed over the range 0.5-9.0 g ml and the sandell's sensitivity for 0.001 absorbance unit is 16.7 ng cm . the method is simple, rapid and free from interferences of several cations and anions which are usually present with nh ion in real samples