Application of Soft Independent Method of Class Analogy (SIMCA) in

12 Application of Soft Independent Method of Class Analogy (SIMCA) in Isomer Specific Analysis of Polychlorinated Biphenyls Downloaded by IMPERIAL COLLEGE LONDON on February 18, 2015 | http://pubs.acs.org Publication Date: July 15, 1985 | doi: 10.1021/bk-1985-0284.ch012

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D. L. STALLING , W. J. DUNN III , T. R. SCHWARTZ , J. W. HOGAN , J. D. PETTY , E. JOHANSSON , and S. WOLD 3

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Columbia National Fisheries Research Laboratory, U.S. Fish and Wildlife Service, Columbia, MO 65201 University of Illinois Medical Center, Chicago, IL 60608 Department of Organic Chemistry, University of Umea, Umea, Sweden

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A p r i n c i p a l components m u l t i v a r i a t e statistical approach (SIMCA) was evaluated and a p p l i e d to interpretation of isomer specific analysis of polychlorinated b i p h e n y l s (PCBs) u s i n g both a m i c r o c o m p u t e r and a main frame computer. Capillary column gas chromatography was employed for separation and d e t e c t i o n of 69 i n d i v i d u a l PCB isomers. Computer programs were written i n ANSII MUMPS to provide a laboratory data base f o r data manipulation. This data base greatly assisted the analysts i n c a l c u l a t i n g isomer concentrations and data management. Applications of SIMCA for quality control, classification, and e s t i m a t i o n of the composition of multi-Aroclor mixtures are described for characterization and study of complex environmental residues. P o l y c h l o r i n a t e d b i p h e n y l s (PCBs) a r e a c l a s s o f s y n t h e t i c c h l o r i n a t e d compounds w i t h a t o t a l of 10 p o s s i b l e p o s i t i o n s f o r c h l o r i n e attachment and 209 p o s s i b l e isomers, although the number of c o n s t i t u e n t s o b s e r v e d i n t e c h n i c a l f o r m u l a t i o n s i s much s m a l l e r (1.-3)• PCBs have been p r o d u c e d by s e v e r a l i n d u s t r i e s worldwide i n the form of t e c h n i c a l f o r m u l a t i o n s (4). Most PCBs p r o d u c e d i n t h e U.S. o r i g i n a t e d as one o f s e v e r a l p r o d u c t s designated as A r o c l o r s and were p r e v i o u s l y m a n u f a c t u r e d by t h e Monsanto Chemical Company (5). The major A r o c l o r s produced were d e s i g n a t e d A r o c l o r s 1 2 4 2 , 1 2 4 8 , 1 2 5 4 , and 1260, where t h e l a s t two d i g i t s designate the percentage of c h l o r i n e by weight i n the m a t e r i a l . Each A r o c l o r i s c h a r a c t e r i z e d by a somewhat d i f f e r e n t d i s t r i b u t i o n o f c o n s t i t u e n t s h a v i n g a c h a r a c t e r i s t i c chromatographic p r o f i l e of about 70 t o 100 chromatographic peaks (1_,3). A f t e r PCBs were i d e n t i f i e d i n 1966 as p o l l u t a n t s i n f i s h and w i l d l i f e ( 6 ) , they were soon r e c o g n i z e d as g l o b a l p o l l u t a n t s 0097-6156/85/0284-0195S11.00/0 © 1985 American Chemical Society

In Trace Residue Analysis; Kurtz, D.; ACS Symposium Series; American Chemical Society: Washington, DC, 1985.

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w i d e l y d i s t r i b u t e d i n the biosphere and i n t i s s u e s of most forms of l i f e , i n c l u d i n g man (7-13). Concern about the o c c u r r e n c e o f PCBs i n t h e e n v i r o n m e n t c e n t e r s on t h e i r p e r s i s t e n c e , bioaccumulaton i n organisms and t o x i c i t y (14, 15). Of a d d i t i o n a l c o n c e r n i s the t h e r m a l c o n v e r s i o n o f PCBs t o polychlorinated dibenzofurans, e s p e c i a l l y when P C B — f i l l e d e l e c t r i c a l transformers a r e i n v o l v e d (16). Further, PCB isomers w i t h no c h l o r i n e atoms s u b s t i t u t e d i n the ortho, ortho'-biphenyl p o s i t i o n s are p a r t i c u l a r l y potent as inducers of a r y l hydrocarbon hydroxylase a c t i v i t y . The potency of c e r t a i n dibenzofurans and non-ortho, ortho c h l o r i n e s u b s t i t u t e d PCBs i n inducing a c t i v i t y of these enzymes i s s i m i l a r t o that of the h i g h l y t o x i c 2,3,7,8tetrachloro-dibenzo-j>-dioxin (15, 17, 18). R e s i d u e s o f PCBs e x i s t as complex m i x t u r e s i n a l m o s t every segment o f t h e e n v i r o n m e n t , and c h a r a c t e r i z a t i o n of t h e s e residues poses a d i f f i c u l t challenge t o the a n a l y s t . R o u t i n e l y , PCBs have been q u a n t i t a t e d by c o m p a r i n g s e l e c t e d peak a r e a s observed i n samples w i t h those i n one of s e v e r a l A r o c l o r mixtures (19, 20). Packed column gas chromatography has u s u a l l y been used i n t h e s e a n a l y s e s , even though t h i s t e c h n i q u e p r o v i d e s poor r e s o l u t i o n of i n d i v i d u a l i s o m e r s and congener groups (21). The problems a s s o c i a t e d w i t h c h a r a c t e r i z i n g m e t a b o l i c a l l y a l t e r e d or weathered PCBs i s a formidable task that r e q u i r e s an a n a l y t i c a l approach w i t h enhanced r e s o l u t i o n . Both the degree and p o s i t i o n of c h l o r i n e s u b s t i t u t i o n on the biphenyl r i n g s i n f l u e n c e the p h y s i c a l - c h e m i c a l and t o x i c o l o g i c a l behavior of the i n d i v i d u a l PCB c o n s t i t u e n t s (15). When PCBs a r e r e l e a s e d i n t o the environment, the o r i g i n a l isomer d i s t r i b u t i o n p a t t e r n o f any PCB f o r m u l a t i o n may be a l t e r e d as a r e s u l t o f s p e c i f i c i n t e r a c t i o n s w i t h the environment (14, 22, 23). Further c o m p l i c a t i o n s a r e encountered i n d e s c r i b i n g the r e s i d u e p r o f i l e s when more t h a n one A r o c l o r m i x t u r e i s encountered i n an ecosystem. Thus, i t i s important t o consider not o n l y t h e t o t a l PCB c o n c e n t r a t i o n i n a s a m p l e , b u t a l s o t o c h a r a c t e r i z e the d i s t r i b u t i o n of i n d i v i d u a l PCB isomers present i n a sample. Because i n f o r m a t i o n d e f i n i n g the d i s t r i b u t i o n of the v a r i o u s PCB isomers among the compartments of l o t i c aquatic ecosystems ( s t r e a m s ) i s l i m i t e d , t h e C o l u m b i a N a t i o n a l F i s h e r i e s Research Laboratory began a d e t a i l e d a n a l y s i s of the d i s t r i b u t i o n of PCBs i n a segment o f t h e m a i n s t r e a m and o f a p o o l o f t h e Upper M i s s i s s i p p i R i v e r . The o b j e c t i v e s of t h i s study were t o model and u n d e r s t a n d t h e h y d r o l o g i c a l and b i o l o g i c a l d i s t r i b u t i o n of PCBs, and to a i d i n a s s e s s i n g the environmental dynamics of PCBs i n the Upper M i s s i s s i p p i River. E c o l o g i c a l l y , Lake Onalaska, the r i v e r pool being s t u d i e d , provides a major s t a g i n g and feeding area f o r m i g r a t i o n of the canvasback (Aythya v a l i s i n e r i a ) i n the M i s s i s s i p p i R i v e r Flyway. About 1200 samples were analyzed by c a p i l l a r y gas c h r o m a t o g r a p h y f o r 69 PCB i s o m e r s . Sample types i n c l u d e d water, suspended s e d i m e n t s , s e d i m e n t s , f i s h , b e n t h o s , and p l a n t s .

Downloaded by IMPERIAL COLLEGE LONDON on February 18, 2015 | http://pubs.acs.org Publication Date: July 15, 1985 | doi: 10.1021/bk-1985-0284.ch012

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The amount and c o m p l e x i t y of d a t a r e s u l t i n g f r o m t h e s e a n a l y s e s prompted us t o s e a r c h f o r an i m p r o v e d method f o r c h a r a c t e r i z i n g and c o m p a r i n g i n f o r m a t i o n gathered from m u l t i component a n a l y s e s of l a r g e numbers of s a m p l e s . M u l t i v a r i a t e s t a t i s t i c s were a p p l i e d i n the p r o c e s s of c h a r a c t e r i z a t i o n of l a r g e numbers of complex r e s i d u e s . Such methods have been r e f e r r e d to as Chemometrics (24). S o f t Independent Method of Class Analogy (SIMCA), a p a t t e r n r e c o g n i t i o n technique based on p r i n c i p a l components (25) was s e l e c t e d t o e v a l u a t e and a p p l y t o the p r o b l e m s of e s t a b l i s h i n g s i m i l a r i t i e s among sample residue p r o f i l e s . The development of a l a b o r a t o r y data management system to a s s i s t i n the c a l c u l a t i o n and o r g a n i z a t i o n of r e s u l t s g r e a t l y enhanced the f e a s i b i l i t y of t h i s approach (26). M a t e r i a l s and Methods Gas C h r o m a t o g r a p h i c A n a l y s i s . We used temperature programmed g l a s s c a p i l l a r y gas chromatography to separate PCB residues. Use of an e l e c t r o n c a p t u r e d e t e c t o r r e q u i r e d an e t f i c a c e o u s sample cleanup f o r isomer q u a n t i t a t i o n (27). These combined techniques o f f e r e d enhanced s e p a r a t i o n s and e n a b l e d us t o i d e n t i f y and q u a n t i t a t e i n d i v i d u a l PCB c o n s t i t u e n t s (JL, 27). S c h w a r t z (27) s e p a r a t e d more t h a n 100 c o n s t i t u e n t s f r o m a 1:1:1:1 m i x t u r e of A r o c l o r s 1242, 1248, 1254, and 1260. A V a r i a n Model 3700 gas c h r o m a t o g r a p h ( V a r i a n A s s o c i a t e s , Palo A l t o , CA) equipped w i t h a " N i e l e c t r o n capture d e t e c t o r was used f o r sample a n a l y s i s . The column was a g l a s s c a p i l l a r y coated w i t h a hydrocarbon s t a t i o n a r y phase having the f o r m u l a 87 176 s t r u c t u r e (24,24-diethyl-19,29-dioctadecylheptatetracontane) (Quadrex Corp., New Haven, CT). The column was a w a l l coated open tube (WCOT) (0.25 mm x 100 m) having a f i l m thickness of a p p r o x i m a t e l y 0.3 m i c r o n s and 3670 t h e o r e t i c a l p l a t e s p e r meter. A 30 m s e c t i o n of the column was c o n d i t i o n e d a t 260 °C overnight and the temperature program r a t e , l i n e a r gas v e l o c i t y , and detector makeup gas were determined by peak r e s o l u t i o n of PCB isomers. C h r o m a t o g r a p h i c c o n d i t i o n s were s i m i l a r f o r a l l sample analyses. The t e m p e r a t u r e program was as f o l l o w s : i n i t i a l temperature 120 °C programmed at 2 °C/min to a f i n a l temperature of 255 °C; i n j e c t o r 220 °C; and d e t e c t o r t e m p e r a t u r e 320 °C. The c a r r i e r g a s , h y d r o g e n , was m a i n t a i n e d a t a column head pressure of 20 p s i . The e l e c t r o n capture d e t e c t o r makeup gas was n i t r o g e n w i t h a f l o w r a t e i n t o the detector of 17 mL/min. The same chromatographic parameters were used i n determining the molar response of the i n d i v i d u a l PCB isomers except, that the area responses were determined w i t h a flame i o n i z a t i o n detector. The f l o w r a t e s of the hydrogen and a i r combustion gases were 30 and 300 mL/min, r e s p e c t i v e l y . Response f a c t o r s needed t o 3

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c a l c u l a t e i n d i v i d u a l congener concentrations were c a l c u l a t e d by using the r a t i o s of flame i o n i z a t i o n t o e l e c t r o n capture response for each standard peak (28, 29). To i n t e g r a t e t h e d i g i t i z e d e l e c t r i c a l s i g n a l s f r o m the gas chromatograph, we used a PDP 1 1 / 3 4 computer ( D i g i t a l Equipment Corp., Maynard, MA) and the computer program PEAK-11, s u p p l i e d from that c o r p o r a t i o n . An o p e r a t i o n a l a m p l i f i e r w i t h v a r i a b l e g a i n was i n t e r f a c e d t o t h e t h e gas c h r o m a t o g r a p h i c a m p l i f i e r output t o a m p l i f y the s i g n a l from the e l e c t r o n capture detector. Data were a c q u i r e d a t t h e r a t e o f 20 p o i n t s p e r s e c and t h e i n t e g r a t i o n and gas chromatographic operations were c o n t r o l l e d by a V a r i a n A u t o s a m p l e r ( M o d e l 8000), w h i c h a l s o d e l i v e r e d a c a l i b r a t e d amount of sample t o the gas chromatographic i n j e c t i o n p o r t . E x t e n s i v e q u a l i t y c o n t r o l and v e r i f i c a t i o n o f a n a l y s e s r e s u l t e d i n r e p r o d u c i b l e r e s u l t s (26). L a b o r a t o r y Data Base System. Data r e p r e s e n t i n g i n t e g r a t e d peak areas were t r a n s f e r e d t o a second PDP-11/34 computer by magnetic tape, where programs w r i t t e n i n D i g i t a l Standard MUMPs (DSM-11) created and maintained the chromatography data base. MUMPs was s e l e c t e d f o r development of t h i s data base because t h i s language i s s t r u c t u r e d t o e f f i c i e n t l y d e a l w i t h s p a r s e a r r a y s . The computer was configured w i t h 96k words of memory, 20M words of d i s k storage, and a 9 t r a c k magnetic tape. The data base programs accomplished the f o l l o w i n g t a s k s : (1) generation of r e t e n t i o n values f o r each PCB isomer peak ( r e l a t i v e to p,p*-DDE) i n every chromatogram; (2) comparison of an A r o c l o r standard, or any mixture of A r o c l o r s , t o a master f i l e of isomers c o n t a i n i n g s t r u c t u r a l i d e n t i f i c a t i o n , number of ortho, o r t h o c h l o r i n e s u b s t i t u e n t s , and flame i o n i z a t i o n response f a c t o r s ; ( 3 ) g e n e r a t i o n o f l i n e a r and l o g a r i t h m i c ( t o accomodate n o n - l i n e a r d e t e c t o r r e s p o n s e ) r e g r e s s i o n e q u a t i o n s f o r each of t h e c o n s t i t u e n t s (69, 92, o r 105 i s o m e r s ) on t h e b a s i s o f A r o c l o r c o n c e n t r a t i o n and a r e a o f each component; ( 4 ) a s s i s t a n c e i n r e s o l v i n g a m b i g u i t i e s i n the process of matching standard peaks to sample c o n s t i t u e n t s ; (5) g e n e r a t i o n o f numerous r e p o r t s on sample p r o c e s s i n g , i n c l u d i n g s t a t u s of sample data, i.e., samples l o g g e d i n , raw c h r o m a t o g r a p i c d a t a matched t o s t a n d a r d s , c o n c e n t r a t i o n o f c o n s t i t u e n t s c a l c u l a t e d from r e g r e s s i o n curve, data a r c h i v e d t o magnetic tape, and (6) p r e p a r a t i o n and magnetic t a p e s t o r a g e o f f i n a l r e p o r t s on c o n c e n t r a t i o n s o f up t o 105 i s o m e r s i n s a m p l e s , w i t h n o t a t i o n s on w h e t h e r t h e measured c o n c e n t r a t i o n f e l l w i t h i n , above, or below the c a l i b r a t i o n range for that c o n s t i t u e n t . A f l o w chart f o r the data a n a l y s i s scheme i s o u t l i n e d i n Figure 1. I n a d d i t i o n t o t h e s e f u n c t i o n s , o t h e r d a t a base programs p r o v i d e d o u t p u t f o r m a t i n g and r e t r i e v a l o f c o n c e n t r a t i o n d a t a from completed a n a l y t i c a l r e p o r t s and t r a n s f e r of these data onto m a g n e t i c tape f o r s u b s e q u e n t e x a m i n a t i o n by SIMCA p r o g r a m s . A d d i t i o n a l f e a t u r e s o f t h e p a t t e r n r e c o g n i t i o n data management 1


Isomer Specific Analysis of PCBs


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subprograms provided peak frequency and ranking summaries w i t h i n each s e l e c t e d sample s e t . Programs were w r i t t e n f o r g r a p h i c p l o t s o f c o n c e n t r a t i o n s o f PCB i s o m e r components and r e l a t e d statistics. A summary of these f u n c t i o n s f o l l o w s : 1• B u i l d the m a t r i x of samples t o output 2. Output the summary m a t r i x of sample i d e n t i t y 3. E d i t the summary m a t r i x 4. B u i l d the set of sample concentrations 5. Output the set of sample concentrations 6. B u i l d the non-zero c o n c e n t r a t i o n matrices 7. Output the non-zero c o n c e n t r a t i o n matrices 8. P l o t c o n c e n t r a t i o n histogram of a sample 9. P l o t means and standard d e v i a t i o n s 10. Generate p r i n c i p a l components p l o t s of data blocks R e s u l t s and D i s c u s s i o n When l a r g e numbers of chromatograms a r e analyzed v i s u a l l y from chart paper or t a b u l a r data, i t i s d i f f i c u l t t o detect minor ( o r perhaps m a j o r ) s i g n i f i c a n t d i f f e r e n c e s t h a t may be p r e s e n t i n samples f r o m d i f f e r e n t l o c a t i o n s o r d i f f e r e n c e s t h a t c o u l d be a t t r i b u t e d t o changing physiochemical processes. A t y p i c a l gas chromatogram o f a PCB m i x t u r e ( F i g u r e 2) r e p r e s e n t s a 1:1:1:1 mixture of A r o c l o r s 1242, 1248, 1254, and 1260. I t contains more than 100 component peaks, of which 69 were s e l e c t e d f o r use i n t h e s e analyses. An a b r e v i a t e d r e p o r t f r o m t h e a n a l y s i s o f t h e m i x t u r e o f A r o c l o r standards j u s t described i s shown i n Table I . The r e p o r t i n d i c a t e s t h e i n d i v i d u a l i s o m e r s t r u c t u r e and degree o f c h l o r i n a t i o n , ortho-, ortho- s u b s t i t u t i o n , isomer c o n c e n t r a t i o n , t o t a l concentration. To i l l u s t r a t e the problems a s s o c i a t e d w i t h e v a l u a t i n g such d a t a , we c o n d u c t e d s e v e r a l s t u d i e s w i t h A r o c l o r s t a n d a r d s and mixtures of these s t a n d a r d s i n an e f f o r t t o d e t e r m i n e what i n f o r m a t i o n could be r e a d i l y obtained w i t h the SIMCA method of p a t t e r n r e c o g n i t i o n ( 3 0 - 3 2 ) . The f o l l o w i n g d i s c u s s i o n i l l u s t r a t e s some of the f e a t u r e s of t h i s approach and describes how the SIMCA method works when a p p l i e d to A r o c l o r mixtures. 1

G e n e r a l D i s c u s s i o n o f SIMCA. Consider a s e r i e s of gas chromatograms obtained on a l a r g e number of samples (N). These samples can a l l c o n t a i n the same number of c o n s t i t u e n t s ( P ) — i n the present study, 69 PCB isomers. Such data can be t a b u l a t e d i n m a t r i x f o r m as i n F i g u r e 3. Each row o f t h e m a t r i x i s a chromatogram w i t h the elements of the m a t r i x , x ^ i * r e p r e s e n t i n g c o n c e n t r a t i o n of peak i . i n sample k. We f i r s t c o n s i d e r t h e h y p o t h e t i c a l case when t h e r e i s no v a r i a t i o n i n composition of the samples, e i t h e r i n r e l a t i o n t o


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Aroclor Standard Mixture 0.35 1242

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the r e l a t i v e c o n c e n t r a t i o n s o f c o n s t i t u e n t s o r i n t h e a b s o l u t e c o n c e n t r a t i o n of isomers. I f our N samples a r e p r o j e c t e d i n t o P. s p a c e , due t o our p r i o r r e q u i r e m e n t o f i d e n t i t y , they w o u l d appear as a t i g h t c l u s t e r , t h e o n l y v a r i a t i o n b e i n g due t o measurement e r r o r .


Table I . Isomer S t r u c t u r e Assignment, Response F a c t o r s , and Concentration i n 1:1:1:1 Mixture of A r o c l o r 1242;1248;1254 and 1260.

Peak: RRT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35

.2681 .2706 .3599 .3695 .3776 .3903 .4615 .4810 .4873 .5173 .5352 .5803 .6031 .6107 .6252 .6390 .6525 .6933 .7145 .7201 .7387 .7441 .7502 .7596 .7758 .806 9 .8237 .8547 .8897 .8990 .9043 .9174 .9320 .9353 .9596

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Chlorines Total Ortho 2 2 2 2 3 2 3 3 3 3 2 4 3 4 3 3 3 4 4 4 4 4 4 4 4 3 5 4 4 5 5 4 4 6 5

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-1 2 2 2 2 0 3 1 3 1 1 1 2 2 2 2 2 2 2 2 0 3 3 1 3

-1 1 4 2

Cone.^ ug/e

Structure 2,2» 2,6 2,5 2,4 3CL 2,4' 2,2',5 2,2',4 2,2',3 2,4',6 4,4' 2,2»,5,6' 2,3»,5 2,2',4,6' 2,4',5 2,4,4* 2,3',4 2,2',5,5» 2,2',4,5» 2,2»,3,5' 2,2',4,4' 2,2',3,4« 2,2',3,3» 2,2',3,4 2,3,4',6 3,4,4» 2,2',3,5,6 2,2',4,5,6' 2,3',4»,5 2,2',3,4,6' 5CL 2,3,3',4» 2,4,4',5 2,2',3,3',6,6» 2,2',4,5,5'

.0098 3.00E-5 .0012 .0046 .0029 .0206 .0468 .0150 .0152 .0096 .0039 .0062 .0076 .0040 .0377 .0313 .0106 .0623 .0226 .0574 .0080 .0085 .0125 .0095 .0159 .0034 .0429 .0107 .0351 .0100 .0252 .0112 .0236 .0002 .0560


2.53E-02 9.00E-05 3.31E-03 1.4OE-02 9.18E-03 6.86E-02 1.53E-01 4.91E-02 5.05E-02 3.10E-02 1.03E-02 2.01E-02 1.93E-02 1.39E-02 1.21E-01 8.5/E-02 3.42E-02 2.00E-01 7.33E-02 1.83E-01 2.72E-02 2.75E-02 4.12E-02 3.08E-02 5.10E-02 1.16E-02 1.37E-01 3,48E-02 1.10E-01 3.14E-02 7.80E-02 3.66E-02 8.01E-02 6.28E-04 1.77E-01

12.

STALLING ET AL.

203


Table I . Continued


Peak

36 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69

RRT

.9832 .9913 1.0205 1.0499 1.0726 1.0815 1.1181 1.1385 1.1613 1.1938 1.2218 1.2382 1.2561 1.2730 1.2998 1.3146 1.3228 1.3358 1.3604 1.3936 1.4280 1.4444 1.4693 1.5032 1.5208 1.5295 1.5454 1.5575 1.5948 1.6119 1.6502 1.7155 1 .7380

Chlorines Total Ortho

5 5 5 6 6 6 6 5 5 6 6 6 6 7 7 7 7 7 7 8 6 7 7 7 8 8 8 8 8 9 8 8 9

2 2 2 3 3 3 3 1 1

-2 2 2 3 3 3 3 3 3 3 1 2 2 2 3 3

-3 4

-2 4

Structure

2,2' ,4,4',5 2,2' ,3 ,3',5 2,2 ,3,3',4 2,2',3 ,5,5',6 2,2',3 ,4',5,6 2,2',3 ,4',5,6' 2,2',3 ,4,5',6 2,3 ',4,5,5' 2,3 ,3',4,4' 6CL 2,2',4 ,4',5,5' 2,2',3 ,3',5,5' 2,2',3 ,4,4',5' 2,2',3,4' ,5,5',6 2,2',3,3 ',4,5,6 2,2',3,3 ',4,5,6' 2,2»,3,4,

i n w h i c h A - p r o d u c t t e r m s have been added t o a c c o u n t f o r t h e v a r i a t i o n i n the data (30). This i s shown i n 3-dimensions below i n F i g u r e 4. T h i s i s a p r i n c i p a l components model i n w h i c h i s the l o a d i n g o f peak i . i n t e r m a., and j t j i s t h e s c o r e o f o b j e c t k i n t e r m a.; b i s a peak s p e c i f i c t e r m and t. i s an o b j e c t o r sample s p e c i f i c term. The v a r i a t i o n about the mean, m-, can be random or s y s t e m a t i c . I f random v a r i a t i o n i s o b s e r v e d i t c a n be due t o measurement e r r o r , and t h i s v a r i a t i o n can be used i n q u a l i t y c a


12.

STALLING ET AL.


205

assurance of the data. I f the measured v a r i a t i o n i s s y s t e m a t i c , i t can be the r e s u l t of c l a s s s p e c i f i c i n t e r n a l v a r i a t i o n , which can be used i n c l a s s i f i c a t i o n or c o r r e l a t i o n s t u d i e s . Cone. Peak 3


ooo o

N-points as a c l u s t e r

Cone. Peak 2

Cone. Peak 1

Figure 4.

C l u s t e r i n g of a Class of I d e n t i c a l Samples.

F i g u r e 5 i l l u s t r a t e s the cases i n w h i c h the d a t a are r e p r e s e n t e d by a p o i n t (A=0), l i n e (A=l) or p l a n e (A=2). A i s the number of p r o d u c t terms i n E q u a t i o n 2. Samples c l u s t e r e d i n a p o i n t r e p r e s e n t r e p l i c a t e a n a l y s e s of a s i n g l e sample i n w h i c h t h e r e i s no v a r i a t i o n o t h e r than measurement e r r o r , and the product term i n Equation (2) i s 0. In these l a s t two s i t u a t i o n s , the d a t a v a r y about the mean, m^, and the p o s i t i o n of each o b j e c t on the l i n e or p l a n e g i v e n by the peak c o o r d i n a t e s . An example of d a t a t h a t w o u l d f o r m a l i n e a r e t h o s e based on an a n a l y s i s of a range of c o n c e n t r a t i o n s of a s i n g l e A r o c l o r (A=l). Data t h a t c o u l d be r e p r e s e n t e d i n a p l a n e r e s u l t f r o m the a n a l y s i s of the f r a c t i o n a l composition of two (or more) A r o c l o r m i x t u r e s (A=2). I n F i q u r e 5, -tk3^ ^ statistical a n a l y s i s of t h i s data set were used as p l o t t i n g coordinates f o r each sample ( T a b l e I V ) . The d a t a were d i s p l a y e d and r o t a t e d a b o u t t h e a x e s i n 3-D u s i n g a D a z z l e r TV g r a p h i c s b o a r d (Cromemco, Inc., Mountain View, CA). F o l l o w i n g t h i s d i s p l a y of the data, the coordinates f o r each sample were used t o generate a 3-D p l o t w i t h a Texas I n s t r u m e n t s P l o t t e r d r i v e n by a MUMPS program i n the l a b o r a t o r y data base. Two g r a p h i c s v i e w p o i n t s were s e l e c t e d t h a t a l l o w e d us t o d i s c e r n t h e t h r e e c l u s t e r i n g o f A r o c l o r s as l i n e s ( F i g u r e 11). The s i n g l e A r o c l o r 1254 s a m p l e ( p o i n t "3") t h a t was composed o f d a t a f r o m an a l t e r n a t e s e t o f d a t a i s r e a d i l y o b s e r v e d i n t h e s e 3-D p l o t s as not being s i m i l a r to any of the other sample types. a

n

d

r o m

t h e

C l a s s i f i c a t i o n To i l l u s t r a t e the use of SIMCA i n c l a s s i f i c a t i o n p r o b l e m s , we a p p l i e d t h e method t o t h e d a t a f o r 23 s a m p l e s o f A r o c l o r s and t h e i r mixtures (samples 1-23 i n Appendix I ) . I n t h i s example, t h e A r o c l o r c o n t e n t o f t h e t h r e e samples o f transformer o i l was unknown. Samples 1-4, 5-8, 9-12 and 13-16, were A r o c l o r s 1242, 1248, 1254, and 1260, r e s p e c t i v e l y . Samples 17-20 were 1:1:1:1 m i x t u r e s o f t h e A r o c l o r s . A p p l i c a t i o n o f SIMCA t o these data generated a p r i n c i p a l components score p l o t ( F i g u r e 12) t h a t shows t h e t r a n s f o r m e r o i l i s s i m i l a r , b u t n o t




STALLING ET AL.

Theta-1 (FIRST

69

OF

105

PEAKS)

F i g u r e 10. P r i n c i p a l C o m p o n e n t s P l o t ( T h e t a T h e t a 2) f r o m A r o c l o r C l a s s e s ( T a b l e I X ) .

1 vs


218



T3

#

12

Tl 3

* $ # 2 3

A r o c l o r 1248 S e r i e s 1:1:1:1 A r o c l o r Mix A r o c l o r 1254 S e r i e s (69/105) 1248 Test 1254 (69) Test T3

T2 3

F i g u r e 1 1 . 3-D V i e w s o f T h e t a V a l u e s D e r i v e d f r o m PC A n a l y s i s o f A r o c l o r s . K e y : * = A r o c l o r 1 2 4 8 ; 6 = 1:1:1:1 M i x t u r e ; # = A r o c l o r 1 2 5 4 ( 6 9 / 1 0 5 p k s ) ; 2 = A r o c l o r 1248 ( t e s t ) ; and 3 = A r o c l o r 1254.


STALLING ET AL.

219



9.9 1254

8.3 6.6 5.0 3.3

1248

1:1:1:1

USED TRANSFORMER OIL 1242 1260 -10.27

-7.84

-5.41

-2.98

-0.55

1.88

4.31

I 6.74

I 9.17

11.60

THETA 1

F i g u r e 12. P r i n c i p a l C o m p o n e n t s P l o t f r o m Five A r o c l o r s C l a s s e s and a U s e d T r a n s f o r m e r F l u i d ( m o s t s i m i l a r t o A r o c l o r 1260).


220


i d e n t i c a l , t o A r o c l o r 1260. A more d e t a i l e d d i s c u s s i o n o f c l a s s i f i c a t i o n using these data i s presented by Dunn et a l . (39).

T a b l e IV. T h e t a V a l u e s from a Three Component P r i n c i p a l C o m p o n e n t s C l a s s M o d e l (A=3) and T o t a l M e a s u r e d T o t a l Concentration of PCBs.


A r o c l o r and SAMPLE # 1248 1 1254 2 1248 3 4 5 6 7 8 10 11 9 12 1:1:1:1 mixture 19 14 13 18 17 15 20 1 6

i 1254 24 26 25 23 27

THETA 1

THETA 2 THETA 3

-0.813

-0.003

-0.180

0.11

0.227 -1.39

CONC.

6 6

0.524 0.351 0.352 -0.0173 -0.0641 -0.645 -1.32 -1.29 -1.52 -2.07

0.621 0.541 0.541 0.369 0.352 0.077 -0.246 -0.236 -0.334 -0.592

0.21 0.216 0.211 0.211 0.225 0.22 0.231 0.231 0.245 0.240

0.76 1.58 1.61 3.46 5.63 6.56 9.85 9.74 10.9 13.7

0.486 0.442 0.255 0.264 0.167 0.0237 -0.587 -0.603

0.570 0.546 0.418 0.430 0.370 0.273 -0.099 -0.122

0.048 0.038 -0.075 -0.089 -0.14 -0.253 -0.629 -0.67

1.48 1.76 3.22 3.24 3.89 5.11 9.7 9.99

0.721 0.733 0.839 0.866 1.08

0.513 0.41 -0.139 -0.353 -1.64

0.173 0.159 0.126 0.112 0.000

0.80 1.38 3.82 4.76 10.7

1

Data Set Obtained from f i r s t 69 of 105 Isomers Quantitated P r e d i c t i o n of Composition

of Unknown Samples PLS.

Because many samples a r e a n a l z y e d i n w h i c h the a n a l y s t i s i n t e r e s t e d i n determining which A r o c l o r mixtures are present, we a p p l i e d the PLS method to the data obtained from the a n a l y s i s of



12.

STALLING ET AL.

221


the used t r a n s f o r m e r f l u i d p r e v i o u s l y d i s c u s s e d . I n o r d e r t o e s t i m a t e t h e A r o c l o r c o n t e n t of t h e p r e v i o u s l y c l a s s i f i e d t h e used t r a n s f o r m e r f l u i d p r e v i o u s l y d i s c u s s e d . In order to e s t i m a t e t h e A r o c l o r c o n t e n t of t h e p r e v i o u s l y c l a s s i f i e d t h e used transformer f l u i d previously discussed. In order to e s t i m a t e t h e A r o c l o r c o n t e n t of t h e p r e v i o u s l y c l a s s i f i e d transformer o i l samples, we obtained a d d i t i o n a l data from the a n a l y s i s of A r o c l o r s of v a r y i n g p r o p o r t i o n s . I n A p p e n d i x I , t h e d a t a a r e o r d e r e d i n an a r r a y and t h e f i r s t f o u r v a r i a b l e s d e s i g n a t e t h e f r a c t i o n a l p a r t o f each A r o c l o r composing t h e sample i n the order 1242, 1248, 1254, and 1260. This composition d a t a r e p r e s e n t s t h e Y - b l o c k and t h e 69 peaks r e p r e s e n t t h e Xblock of data analyzed w i t h the PLS-2 program.

Table V. S t a t i s t i c a l Summary f o r A=3 P r i n c i p a l A n a l y s i s of A r o c l o r Samples.

StepPar. 0 1 2 3 4

Alpha BetaBe t a Beta-

A 0 0 1 2 3

NDF 1862 1794 1700 1608 1518

SS 4.36E+03 2.25E+03 5.83E+02 1.36E+02 5.24E+01

SD

1 -SD/SDY

1.53E+00 1.12E+00 5.86E-01 2.91E-01 1.86E-01

0.000 0.268 0.617 0.810 0.879

Components SIMCA

SS(TETA) 0. 0. 1.7E+03 4.5E+02 8.4E+01

ITET 0 14 9 17

The samples of unknown composition—21-23 and samples 1-20, 24-34 ( A p p e n d i x I ) w e r e t h o s e o f A r o c l o r s o f v a r i a b l e composition. V a r i a b l e s 5-73 are isomer concentrations ( V a r i a b l e 74, t h e t o t a l PCB c o n c e n t r a t i o n i n ppm was n o t i n c l u d e d i n t h e analysis). V a r i a b l e s 5-73 represent the f r a c t i o n a l composition or i s o m e r p r o p o r t i o n a l c o n c e n t r a t i o n v a l u e s . Representative c o n c e n t r a t i o n histograms of the data s e t are presented i n F i g u r e 13. Four PLS components were e x t r a c t e d and then used to e s t i m a t e the A r o c l o r content of the unknowns and of a standard sample (No. 24). The A r o c l o r standard i s a mixture of three A r o c l o r s i n the r a t i o of 033:0.33:0:0.33. Chromatograms of the samples f o r which the PLS e s t i m a t e s were made ( T a b l e V I ) were s i m i l a r when compared to a chromatogram of a s i m i l a r m i x t u r e of standards. The p a r t i a l l e a s t squares (PLS) method has been a p p l i e d t o s t r u c t u r e a c t i v i t y p r o b l e m s by Wold ej: a l . ( 3 8 ) . Recently, Lindberg e t a l . (40) employed t h i s approach t o r e s o l v e mixtures of humic a c i d and l i g n i n s u l f o n a t e on t h e b a s i c o f f l u o r e s c e n c e spectra. This example demonstrates that the PLS method gives a s t a b l e e s t i m a t e of t h e Y - b l o c k , even though t h e r e a r e many more Xv a r i a b l e s than samples, a c o n d i t i o n that removes the p o s s i b i l i t y of a p p l y i n g m u l t i p l e r e g r e s s i o n . Another advantage of the method


222


AROCLOR

.125

1254 C*9> 2 . 9 0 3 ng


.1 .875 .86 .825 _

a 18

15

28

25

L-il P«ok

AROCLOR

.125 _ .1

48 *

1254 +

45

58

55

1260 I:J 3.044 n 0

-

.875 CO O 0.

a o o

18

16

L, 28

J l , , , 1J i l l i l j l l i l l , 25 38 36 48 45 P.ak • AROCLOR

175 _ .16 125

. , 11 88 66

78

1260 C#13) 3 . 1 8 5 ng

-

876 .86

-

8 28

,1 ll .1,

26

ll.,..lllmi.

3 8 3 6 4 8 4 6 5 8 6 6 P«ok •

TRANSFORMER O I L C * 2 I ) 1862 ng

.16 .126 _ .1 .875 .85 _ .826 _

a 6

18

ll.lM 16 28

26

Jlii

38 36 48 P«ok *

F i g u r e 13. F r a c t i o n a l C o m p o s i t i o n T r a n s f o r m e r F l u i d and A r o c l o r s .

66

68

66

78

H i s t o g r a m s o f Used


12.

STALLING ET AL.

223



t h a t makes i t a t t r a c t i v e f o r use i n a n a l y t i c a l p r o b l e m s i s i t s computational e f f i c i e n c y and s i m p l i c i t y , which makes i t p o s s i b l e t o use m i c r o c o m p u t e r s and m i n i c o m p u t e r s t o c a r r y out such calculations• The SIMCA software i s a v a i l a b l e i n two forms, both developed by Wold (25., 31): 1) an i n t e r a c t i v e , F o r t r a n v e r s i o n w h i c h r u n s on C o n t r o l Data Corporation (CDC) machines, and 2) an i n t e r a c t i v e v e r s i o n , SIMCA-3B. A d d i t i o n a l i n f o r m a t i o n on t h e s e programs i s contained i n Appendix I. Only the SIMCA-3B v e r s i o n contains the CPLS-2 program used f o r PLS a n a l y s i s .

Table VI. F r a c t i o n a l Composition of A r o c l o r s i n Transformer O i l s Estimated by p a r t i a l l e a s t squares.

Aroclor

i

Sample number

1242

1248

1254

1260

21

.03

.03

.08

.84

22

.03

.03

.08

.84

23

.03

.03

.08

.84

25

.37 (.33)

.36 (.33)

.05 (.00)

.24 (.33)

1

A c t u a l composition

Environmental A p p l i c a t i o n s To i l l u s t r a t e the environmental a p p l i c a t i o n of the SIMCA method we examined a s e t of i s o m e r s p e c i f i c a n a l y s e s of s e d i m e n t samples. The d a t a examined were d e r i v e d f r o m more t h a n 200 sediment samples taken from a study s i t e on the Upper M i s s i s s i p p i R i v e r (41). These a n a l y t i c a l data were t r a n s f e r r e d v i a magnetic tape f r o m the l a b o r a t o r y d a t a base t o the Cyber 175 computer where p r i n c i p a l component a n a l y s i s were conducted on the isomer c o n c e n t r a t i o n data (ug/g each isomer). The f i r s t p r i n c i p a l component v a l u e s ( T h e t a 1) f o r each sample were determined and these values were c o r r e l a t e d w i t h the t o t a l PCB c o n c e n t r a t i o n ( F i g u r e 14) recorded f o r each sample i n a separate computer data base t h a t c o n t a i n e d o t h e r e n v i r o n m e n t a l d a t a such as h y d r o l o g y and s e d i m e n t t e x t u r e . The r e s u l t s i n d i c a t e d that c e r t a i n samples deviated by f a c t o r s of about two. Upon examining the sample records, the recorded d i l u t i o n v a l u e s



224


0.024

«

%

1

3

.001 ).000 \ >.O01

I 6 9 U 6 t I RI966 G ! 1U 7986 COO 9 C56S7 « 1 6 IH 9137R >P68S7«8U 769 7 18 9 86L 1U 1 1 61 R 6 3

1.004 1.005 .00

0.C3

C.06

>.09

0.12

0.15

0.18

0.21

0.24

0.27

0.30

0.33

T o t a l PCB C o n c e n t r a t i o n , ppm F i g u r e 1 5 . P l o t o f T h e t a 2 v s . T o t a l PCB C o n c e n t r a t i o n m e a s u r e d i n 201 L a k e O n a l a s k a S e d i m e n t S a m p l e s .


226



Appendix I . This appendix contains some of the data generated f o r the SIMCA and PLS analyses. The complete data s e t i s a v a i l a b l e from the a u t h o r s . Upon r e q u e s t t h e d a t a w i l l be p r o v i d e d on 8" s i n g l e d e n s i t y s i n g l e s i d e d f l o p p y d i s k s i n IBM 3740 f o r m a t f o r CP/M based s y s t e m s o r on 5 1/4" d o u b l e s i d e d d o u b l e d e n s i t y f l o p p y d i s k f o r t h e IBM/PC o r o t h e r MS/DOS based c o m p u t e r s . The requestor, however, must supply a properly formated floppy d i s k . S o f t w a r e A v a i l a b i l i t y . The SIMCA s o f t w a r e i s a v a i l a b l e i n two f o r m s , b o t h d e v e l o p e d by Wold ( 2 5 ) : 1) an i n t e r a c t i v e , F o r t r a n v e r s i o n w h i c h r u n s on C o n t r o l Data C o r p o r a t i o n (CDC) m a c h i n e s . The second s e t of programs a r e an i n t e r a c t i v e m i c r o c o m p u t e r v e r s i o n , SIMCA-3B, a r e a v a i l a b l e from P r i n c i p a l Data Components, 2505 Shepard B l v d . , C o l u m b i a , MO 65201. The SIMCA-3B p a t t e r n r e c o g n i t i o n programs i n c l u d e s t h e CPLS-2 program used f o r PLS a n a l y s i s and a r e a v a i l a b l e f o r CP/M ( D i g i t a l R e s e a r c h , P a c i f i c Grove, CA) and MS-DOS ( M i c r o s o f t Corporation, B e l l u e v e , WA) f o r 8088 o r 8086 based microcomputers. The F o r t r a n v e r s i o n used i n t h i s study was l o c a t e d a t t h e Computer Center a t t h e U n i v e r s i t y of I l l i n o i s a t Champaign/Urbana. The F o r t r a n v e r s i o n i s u s e f u l f o r a n a l y s i s of v e r y l a r g e d a t a s e t s , i . e . 400 x 70 m a t r i c e s . The SIMCA-3B v e r s i o n f o r m i c r o c o m p u t e r s y s t e m s i s i n t e r a c t i v e , menu d r i v e n , and i s a p p l i c a b l e t o i n t e r m e d i a t e s i z e d data sets and runs under CPM or MS-DOS. I n t h i s study, the SIMCA-3B program—CPLS-2, was used t o o b t a i n the r e s u l t s i n the PLS examples discussed. An e a r l i e r F o r t r a n v e r s i o n of SIMCA i s a v a i l a b l e f o r use i n the ARTHUR package a v a i l a b l e from Chemical I n f o r m a t i o n Systems, Box 2227, F a l l s Church ,VA. R e c e n t l y , t h e o p e r a t i n g s y s t e m was changed on t h e CDC Cyber computer s y s t e m a t t h e U n i v e r s i t y o f I l l i n o i s . The new o p e r a t i n g s y s t e m does n o t a l l o w t h e e a r l i e r SIMCA-2T v e r s i o n used t o perform the environmental analyses t o o p e r a t e c o r r e c t l y . The a u t h o r s e x p e c t t h a t a new v e r s i o n of SIMCA w i l l be i n s t a l l e d t h a t w i l l f u n c t i o n w i t h t h e c u r r e n t operating system i n use on the CDC Cyber computer.


12.

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227

P a r t i a l Summary of Data from the Gas Chromatographic A n a l y s i s ot A r o c l o r , A r o c l o r M i x t u r e s , and Transformer O i l analyses.


Table 1. I d e n t i t y of Samples A n a l y z e d — A r o c l o r 1242, 1248, 1254, 1260, Their M i x t u r e s and a Transformer O i l . Data are i n c l u d e d i n t h i s appendix f o r sample numbers designated w i t h an a s t e r i k .

SIMCA ID 1* 2 3 4

Description A r o c l o r 1242 R e p l i c a t e A r o c l o r 1242 R e p l i c a t e A r o c l o r 1242 R e p l i c a t e A r o c l o r 1242 R e p l i c a t e

5* 6 7 8

Aroclor Aroclor Aroclor Aroclor

1248 1248 1248 1248

Replicate Replicate Replicate Replicate

9* 10 11 12


1254 1254 1254 1254


13* 14 15 16


1260 1260 1260 1260


17* 18* 19* 20*

Aroclor42:48:54:60 A r o c l o r 4 2 : 4 8 :54:60 Aroclor42:48:54:60 Aroclor42:48:54:60

21* 22* 23*

Used Transformer O i l R e p l i c a t e Used Transformer O i l R e p l i c a t e Used Transformer O i l R e p l i c a t e

24 25 26 27 28 29 30 31 32 33

Aroclor Aroclor Aroclor Aroclor Aroclor Aroclor Aroclor Aroclor Aroclor Aroclor

42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60 42:48:54:60

1:1:1:1 1:1:1:1 1:1:1:1 1:1:1:1

1:1:0:1 1:0:1:1 0:1:1:1 1:1:0:0 1:0:1:0 1:0:0:1 0:1:1:0 0:0:1:1 0:1:0:1 1:1:1:1


Z Z 6


Table I I . Data M a t r i x O r g a n i z a t i o n f o r A r o c l o r s and Samples.

Data M a t r i x - V a r i a b l e # Sample #


K

1

1242) 6( peak 2 ) 11 16 21 26 31 35 41 46 51 56 61 66 71

2

TD code

2(1248) 7(peak 3)

72

3(1254) 8(peak 4)

73(peak 69)

4(1260) 9

1 10

3

7 4 ( T o t a l cone.)

Weight f r a c t i o n each A r o c l o r i n sample v a r i a b l e 1-4 ^Variables 5-73 are f r a c t i o n a l c o n c e n t r a t i o n of each PCB isomer 'Variable 74 designates t o t a l PCB c o n c e n t r a t i o n i n sample Table I I I . R e p r e s e n t a t i v e Analyses of A r o c l o r s , T h e i r Mixtures and a T r a n s f o r m e r O i l Sample. R e f e r t o T a b l e 2 f o r key t o d a t a organization.

100 0 .8347 .07662 .2134 .08603 .04002 .1051 .01593 0 0 0 0 0 0

Sample # ID code 1 1 42 0 .03722 .3023 .07048 .3437 .02791 .0355 .09709 .02423 0 0 0 0 0 0

0 .1324 .3691 .02987 .3375 .07272 .1661 0 .02633 0 0 0 0 0 0

0 .1501 .1762 .5528 .3169 .1301 .08603 .03421 0 .01582 0 0 0 0 7.511


.3318 .6295 0 1.14 .09121 .1613 .2138 .02422 0 .01318 0 0 0 0

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STALLING ET AL.

IsomerSpecific Analysis of PCBs

229


Table I I I . Continued

0 0 .3688 .1108 .09049 .1164 .1572 .1657 .06115 0 0 0 .0009057 0 0 0 0 0 0 0 .001386 .2877 .003889 .07539 .1595 .1752 .005103 .02406 .001136 0 0 0 0 0 0 0 .1134 0 0 .3606 .5124 .2944 .01198 .01951 0

5 5 48 100 0 .09205 .08407 .6112 .04218 .1294 .1605 .09849 0 0 0 0 0 6.426E-05 9 9 54 0 0 0 0 .2006 0 .1281 .03496 .1657 .07247 .02599 .002069 0 0 0 13 13 60 0 0 0 0 0 0 0 .0004755 .006675 .07934 .01567 .08182 .02128 .02727 .04784

0 0 .1105 .03458 .4933 .1092 .3208 0 .1533 0 0 0 0 1.463E-05 0

0 .02243 .07285 .3342 .5239 .2177 .1477 .1479 0 .09543 0 0 0 0 6.257

.02185 .04143 0 .4488 .1222 .05379 .3446 .09148 0 .05943 0 0 .0003501 0

100 0 0 0 .03684 0 .06263 .03043 .3222 0 .1777 .001326 .007326 0 0

0 0 0 0 .07303 .01534 .013 97 .3352 .04839 .1939 .01992 0 .0102 0 2.903

0 0 0 0 0 0 .01731 .09876 .007758 .06609 0 .002222 0 0

0 0 0 0 0 0 0 .06472 .02628 .07441 .2802 .04352 .3146 .03142 .009139

100 0 0 0 0 0 0 .1251 .1837 .0009664 .01874 0 .1039 .02323 3.185

0 0 0 0 0 .02807 0 0 .02169 0 .1711 .006068 .06354 .002931

Table I I I . Continued on next page


230



Table I I I . Continued

25 0 .2019 .03203 .04948 .03584 .1765 .04801 .04109 .1798 .2308 .1034 .01464 .007217 0 25 0 .1923 .02852 .04677 .03311 .1754 .04581 .03923 .1755 .2197 .09693 .01202 .006168 0 25 0 .1979 .02768 .04811 .03671 .1798 .04658 .04075 .1816 .2255 .09807 .01253 .006722 0

17 17 M4 25 .007108 .06352 .02606 .2394 .01305 .07449 .05987 .08646 .05681 .01501 .03089 .007318 .009673 .01765 18 18 M4 25 .009318 .06195 .0246 .2254 .02247 .06777 .0564 .08372 .05492 .01502 .02829 .006532 .008577 .01566 19 19 M4 25 .00758 .06332 .02566 .2343 .02365 .07212 .05797 .08714 .05516 .01544 .02874 .00762 .009386 .0158

25 .02049 .0797 .01205 .156 .02929 .09968 .03558 .1563 .02459 .1661 .01593 .103 .01155 .002694

25 .01411 .04155 .1385 .1621 .06368 .04474 .1951 .08263 .09232 .01465 0 .04175 .007575 4.385

.05351 .1062 0 .2308 .03699 .03058 .09625 .05449 .01062 .03886 .06061 .002988 .02351 .0004781

25 .02033 .07673 .01163 .1456 .03049 .0975 .03511 .1494 .02173 .1514 .01499 .09292 .01005 .002565

25 .01366 .037 57 .1362 .1597 .06241 .04221 .1943 .07 889 .0869 .01265 0 .03756 .007134 4.186

.0582 .1012 0 .2158 .03718 .02041 .09346 .05288 .01055 .03402 .05624 .002718 .02181 0

25 .01591 .07692 .01181 .1521 .03228 .09911 .03613 .1496 .02203 .1564 .01439 .09556 .01079 .001706

25 0 .03998 .139 .1627 .06273 .04306 .198 .08243 .09154 .0134 0 .03932 .006948 4.22

0 .1035 0 .2205 .0366 .01992 .0963 .05478 .01029 .03546 .05881 .002419 .02241 0



12.

STALLING ET AL.


Table I I I . Continued 20 20 M4 25 25 0 0 .1888 .05618 .029 .02383 .04563 .2313 .03259 .0219 .1742 .07348 .04368 .05558 .03871 .08279 .1776 .05508 .2167 .0147 .09493 .0272 .01184 .007262 .006812 .008346 0 .01538 21 21 TO 0 0 0 0 21.21 9.022 0 0 9.456 29.72 5.23 0 67.07 11.2 16.32 19.48 7.393 2.339 169.9 41.68 259.6 10.67 141.5 39.53 9.323 8.306 10.12 18.16 0 27.11 022 22 TO 0 0 0. 0 18.84 6.861 0 0 9.354 28.37 4.054 0 68.15 11.62 15.17 17.98 6.871 2.331 167.6 42.73 258.6 10.65 140.7 39.08 8.846 8.124 10.08 17.99 0 26.88

231

25 .01953 .07373 .01114 .1486 .03021 .09438 .03355 .1486 .02429 .1513 .01298 .09327 .01053 .001 846

25 .02258 .03659 .1375 .159 .06214 .04086 .1881 .07911 .08819 .01244 0 .03842 .006725 4.101

0 .1012 0 .2149 .03436 .0217 .09305 .05164 .008697 .03461 .05699 .002228 .02261 0

0 0 7.668 0 18.87 3.79 13.59 25.79 36.12 17.97 150.3 20.73 156.3 20.98 6.732

0 0 4.709 22.01 16.88 6.906 0 90.13 83.84 19.92 11.58 9.535 62.34 10.67 1962

0 9.761 0 37.65 0 0 13.89 10.21 9.548 7.416 82.64 0 39.39 0

0 0 6.402 0 16.44 0 13.79 24.69 36.60 18.34 150.1 20.85 156.7 20.90 6.672

0 0 4.596 20.97 16.38 7.090 0 89.59 82.98 18.26 11.48 9.035 61.77 10.63 1929.

0 7.651 0 36.33 0 0 13.65 8.900 9.401 69.10 81.87 0 39.50 0

Table I I I . Continued on next page



232


Table I I I . Continued 023 23 TO 0 0 0 0 8.285 20.07 0 0 27.98 8.918 0 0 10.25 63.37 19.00 15.78 2.185 0 39.50 161.7 9.602 244.7 36.90 131.9 7.868 8.368 16.73 9.241 24.92 0

0 0 5.973 0 15.53 0 13.64 24.82 37.18 17.65 141.9 19.59 146.8 19.50 6.579

0 0 4.554 21.05 15.96 6.221 0 86.27 79.38 20.34 10.87 8.435 56.95 9.806 1835

0 9.198 0 33.38 4.408 0 12.98 8.967 9.282 6.783 77.59 0 36.46 0

Literature Cited 1. Ballschmiter, K.; Zell, M. Freshenius Z. Anal Chem. 1980, 302, 20. 2. Albro, P. W.; Corbett, J. T.; Schroeder, J. L. J . Chromatogr. 1981, 205, 103. 3. Bush, B.; Connor S.; Snow, J . J. Assoc. Off. Anal. Chem. 1982, 65, 555. 4. Hutzinger, O.; Safe, S.; Zitko, V. in "The Chemistry of PCB's," CRC Press, Cleveland, OH, 1974. 5. Brinkman, U. A. Th. de Kok, A. in "Topics in Environmental Health, Halogenated Biphenyls, Terphenyls, Naphthalenes, Dibenzodioxins and Related Products, Kimbrough, R. D., Ed. ; Elsevier/North Holland Biomedical Press: New York , 1980; 2-4. 6. Jensen, S. New Sci. 1966, 32, 612. 7. Zell, M.; Ballschmiter, K. Fresenius Z. Anal. Chem. 1980, 304., 337 8. Koeman, J . H.; Debrouw, M.C.; De Vos, R.H. Nature (Lond.) 1969, 221, 1126. 9. Biros, F.J.; Walker, A.C.; Medbery, A.; Bull. Environ. Contam. Toxicol. 1970, 5, 317. 10. Fishbein, L. J. Chromatogr. 1972, 68, p 345. 11. Hammond, P. B.; Nisbet, I.C.T.; Sarofim, A.F.; Drurry, W.H.; Nelson, W.; Rall, D. P. Environmental Impact. Environ. Res. 1972, 5, 249. 12. Bush, B.; Tumasonis, C.F.; Baker, F.D. Arch. Environ. Contam. Toxicol. 1982, 28, 97. 13. Mes, J.; Davies, D.J.; Turton, D. Bull. Environ. Contam. Toxicol. 1982, 28, 97. 14. Bandera, S.; Sawyer, T.; Campbell, M.A.; Robertson, L.W.; Safe, S. Life Sciences 1982, 31, 517.



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of

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RECEIVED March 25, 1985


Application of Soft Independent Method of Class Analogy (SIMCA) in

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