Quantitative Spark Source Mass Spectrometry

Abstract

knowledge of t h e chemical c o m p o s i t i o n of m i n e r a l s , a l l o y s , r e s i d u e s and h i g h p u r i t y m a t e r i a l s . Spark s o u r c e mass s p e c t r o m e t r y (SSMS) i s p l a y i n g a n e v e r i n c r e a s i n g r o l e i n t h e f i e l d of m a t e r i a l s c h a r a c t e r i z a t i o n by t r a c e m u l t i e l ement a n a l y s i s . IJnder i d e a l c o n d i t i o n s SSMS c a n b e used t o a n a l y z e for a l l s t a b l e e l e m e n t s a t l e v e l s r a n g i n g from a l m o s t 1% t o a few p a r t s p e r b i l l i o n .Normally no p r e c o n c e n t r a t i o n i s r e q u i r e d and sample p r e t r e a t m e n t i s m i n i m a l . Furthermore, SSMS d o e s n o t e x h i b i t order-of-magnitude v a r i a t i o n s i n s e n s i t i -v i t y for d i f f e r e n t e l e m e n t s i n a g i v e n matrix as do n e u t r o n a c t i v a t i o n a n a l ys i s and atomic a b s o r p t i o n s p e c t r o s c o p y . However, SSMS has s u f f e r e d from a r ep u t a t i o n of b e i n g o n l y a s e m i q u a n t i t a t i v e t e c h n i q u e b e c a u s e o f t h e d i f f i c u l t y i n v o l v e d i n p r o p e r l y c a l i b r a t i n g t h e a n a l y t i c a l d a t a o b t a i n e d . C o n t r i b u t i n g t o t h e problem h a s been t h e slow r e c o g n i t i o n a n d s u b s e q u e n t e l i m i n a t i o n of v a r i o u s s y s t e m a t i c e r r o r s a f f e c t i n g t h e a n a l y s i s .A s e m i q u a n t i t a t i v e e s t i m a t e of t r a c e element c o n c e n t r a t i o n can b e made from a v i s u a l comparison o f e x p o s u r e s n e c e s s a r y t o produce j u s t d e t e c t a b l e l i n e s from a t r a c e element i s o t o p e and a n i s o t o p e o f a r e f e r e n c e element.Trace element c o n c e n t r a t i o n s c a n t h e n b e c a l c u l a t e d from t h e f o l l o w i n g equa-where t h e s u b s c r i p t s s and i r e p r e s e n t t h e i n t e r n a l s t a n d a r d and t r a c e e l e m e n t r e s p e c t i v e l y , C -c o n c e n t r a t i o n i n ppm(wt.1, X -c o n c e n t r a t i o n o f i n t e r n a l s t a nd a r d , Ezbeam m o n i t o r e x p o s u r e i n coulombs o f c h a r g e f o r e q u i v a l e n t peak i nt e n s i t i e s of t h e t r a c e element and s t a n d a r d s p e c i e s ( j u s t d e t e c t a b l e l i n e s

Improvement in the analysis of ashes from coal by spark source mass spectrography

“…The homogeneity of the sample electrodes is important (28,(173)(174)(175)(176)(177). Care must be taken not only to insure the homogeneity of the sample and sample-graphite mixture, but also the homogeneity of the internal standard in the electrodes if the doping method is used (172,178). Homogenizing methods vary from simple grinding and thorough mixing to complex methods of dilution by multiple fusion (35,188).…”

“…The sensitivity is limited for low mass ions and the +2 ions of the transition metals by the back ground fog caused by the sample matrix and the graphite in the electrodes (191). A number of methods of correction for errors caused by spectral interferences have been devised (36,172,175,177,178,185,189,192). The sensitivity of the photographic emulsion is also dependent on the mass and energy of the impinging ions (31, 36,173,175).…”

“…The choice of the internal standard can affect the precision and accuracy (172,175,178,185,190). A number of criteria for the selection of internal standards have been published (172,175,178,190).…”

“…A number of criteria for the selection of internal standards have been published (172,175,178,190). The accuracy of the determination of the relative sensitivity of this method for elements in a certain sample matrix affects the precision and accuracy of the analysis (28,31,(34)(35)38,(171)(172)(173)(174)(175)(176)(177)(178)(180)(181)(182)185,(188)(189)(190)(192)(193)(194)(195)(196).…”

“…The accuracy of the determination of the relative sensitivity of this method for elements in a certain sample matrix affects the precision and accuracy of the analysis (28,31,(34)(35)38,(171)(172)(173)(174)(175)(176)(177)(178)(180)(181)(182)185,(188)(189)(190)(192)(193)(194)(195)(196). The relative elemental sensitivity is dependent on the elemental ionization potential (36,38,172,175,176,180,185,189,192), volatility (35,36,38,172,175,176,180,182,185,189,192), and ionization cross-section, which is determined by the atomic covalent radius (172,175,…”