ABSTRACT
Saka i a n d M o r i [2] preconcentra ted cobal t w i t h N - ( d i t h i o c a r b o x y ) sarcosine a n d A m b e r l i t e X A D - 4 res in . C o b a l t reacted w i t h N - ( d i t h i o - ca rboxy)sa rcos ine to f o r m a 1:3 cobal t N - ( d i t h i o c a r b o x y ) sarcos ine c o m p l e x w h i c h w a s stable i n 4 M h y d r o c h l o r i c ac id . T h e c o m p l e x so f o r m e d w a s adso rbed o n a c o l u m n of A m b e r l i t e X A D - 4 c o p o l y m e r f r o m ac id s o l u t i o n a n d e lu ted w i t h 1 0 m l of a 1:1:3 v / v , m i x t u r e of 1 . 0M a m m o n i a s o l u t i o n (pH9) , 0 . 1 M E D T A , a n d me thano l . T h e absorbance of the e lu ted chelate w a s de t e rmined at 320nm. The ex t inc t ion coefficient w a s 21500L m o l 1 c m _ 1 . Interferences were e l i m i n a t e d b y the a d d i t i o n of E D T A after che la t ion of cobalt . T h e coppe r c o m p l e x w i t h N - ( d i t h i o - carboxy)sarcosine w a s pa r t l y adso rbed because of the s l o w rate of d e c o m p o s i t i o n b y E D T A . M o s t che la ted coppe r c o u l d be e lu ted w i t h h y d r o c h l o r i c a c i d a n d any co-e lu ted w i t h the cobal t chelate c o u l d be d e c o m p o s e d b y heat ing . C o b a l t en r i chmen t factors of at least 100 were ob ta ined a n d the m e t h o d c o u l d be a p p l i e d to de t e rmina t i on of cobal t at the n g m l _ 1 l eve l .
