× standard geological materials and sea water samples.   Experimental Instrumentation and measurements Spectrophotometric determinations were done with a Hitachi 3210 UV/Vis spectrophotometer using 10 mm quartz cells. Plasma scan model 710 sequential inductively coupled plasma optical emission spectrometer with plasma scan multitasking computer and peristaltic pump was used for emission measurements applying the following conditions. Radio frequency (Rf) 27.12 MHz