DIRECT DETERMINATION OF COPPER IN GLASS SAMPLES BY GRAPHITE-FURNACE AAS WITH SLURRY-INTRODUCTION

A simple method was investigated for the direct determination of copper in glass samples using graphite furnace AAS with a slurry method. This method is based on the atomization of copper by the introduction of powdered glass samples suspended in a 10% glycerin solution as dispersant into a furnace. A glass sample (less than 10 mum in size) of 1 approximately 30 mg containing less than 0.5 mug of copper is placed in a polystyrene test tube (15 ml). Then, 5.0 ml of a 10% glycerin solution is added to the tube, and the sample is dispersed into the solution by an ultrasonic agitator for 30 s. After this procedure, 10 mul of the homogeneous suspension and an equal volume of 5% ammonium fluoride are injected into a graphite furnace. The optimal thermal programs are obtained as follows: drying at 160-degrees-C for 60 s, ashing at 700-degrees-C for 30 s, and atomization at 2600-degrees-C for 5 s in an argon atomosphere (flow rate: 2.0 l/min). The 324.7 nm line was used for the determination of copper using the peak-area mothod; a background correction was made using a deuterium lamp. The relative standard deviation was 2.4% for 6 measurements on 11.5 mug/g copper in a bottle glass.