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Anal. Chem. 1983, 55,2255-2260
2.5 X M of TRA or EDTA, both Mo(V1) and Mn(I1) in the concentration range 0 to 5 X M were effectively masked while determining concentrations of vanadium(V) or Fe(I1) (Table XI). For the determination of the concentration of vanadium(V) in samples containing iron, the masking technique proved futile. Hence, in the selection of and extraction technique, vanadium(V) is accurately determined by selective solvent extraction of Fe(1I) from the sample with isobutyl methyl ketone (IBMK) (9) (a 10 mL sample was shaken twice with 10 mL of IBMK for 3 min each and then with 5 mL of 1hexanol for 2 min to remove traces of IBMK miscible in sample). A perusal of Table I1 shows the sensitivity of the method. The overall potential measured with reference to the calomel electrode varied slightly from experiment to experiment, but the values of the induction periods and reaction rate were highly reproducible. Since only arbitrary values of potential are considered, cation concentration determinations were not affected. In conclusion the kinetics of oxidation of hydroxylamine by acidic bromate provide a double-check method for the accurate determination (maximum 4% deviation) of vana-
dium(V) and iron(I1) in the concentration range 5 X lo4 to 10 X M, even in the presence of different cations or either organic or inorganic ligands.
ACKNOWLEDGMENT The author is thankful to S. 0. Wandiga, Department of Chemistry, for the research facilities. Registry No. V, 7440-62-2;Fe, 7439-89-6;",OH, 7803-49-8; potassium bromate, 7758-01-2;hydroxylamine sulfate, 10039-54-0. LITERATURE CITED Mottola, H. A.; Mark, H. B., Jr. Anal. Chem. 1982, 5 4 , 62R. Harris, W. E.; Kratochvil, B. "An Introduction to Chemical Analysis"; Saunders College Publlshing: Philadelphia, PA, 1981; p 347. Fukasawa, T.; Yamane, T. Sunsekl Kagaku 1977, 26, 300. Dickson, E. L.; Svehla, G. Microchem. J . 1979, 24,509. Pantel, S. Anal. Chlm. Acta 1979, 104, 205. Sullivan, J. C.; Thompson, R. C. 1979, 18, 2375 Jonnalagadda, S. B., unpublished work. Schwarzenbach, G.; Flaschka, H. "Complexometric Titrations"; translated by H. M. N. H. Irving; Methuen & Co. Ltd.: London, 1969; p 129. Akama, Y.; Nakai, T.; Kawamura, F. Analyst (London) 1981, 106, 250.
RECEIVED for review February 22, 1983. Accepted June 15, 1983.
Laser Microprobe Mass Analysis of Plastic-Contaminated Asbestos Fiber Surfaces Johan K. De Waele,* J. J. Gybels, E. F. Vansant, and F. C. Adams
Department of Chemistry, Universitaire Instelling Antwerpen (U.I.A.),Universiteitsplein 1, B-2610 Wilrijk, Belgium
Standard U.I.C.C. asbestos samples are often contamlnated wlth organic addltlves of polyethylene packing material. Laser microprobe mass analysis when used at low laser lrradlance eondltlons is able to detect specific organlc surface contaminants on indivldual fibers wlth detectlon llmlts of better than 500 pg g-' and wlth a shot-to-shot reproduclbllltyof ca. 20%.
ena were investigated semiquantitatively with laser microprobe mass analysis (LAMMA) and quantitatively with gas-liquid chromatography; gas chromatography/mass spectrometry was necessary for the identification of the particular impurity. It proved to be phthalates originating from the polyethylene bags in which the material had been stored.
The hazards for human health associated with the extraction and handling of various members of the asbestos materials are now well established. There is strong evidence that associates occupational exposure to asbestos fibers to a high incidence of lung cancer, pleural and peritoneal mesothelioma, and an excess risk of gastrointestinal cancer (1-4). However, a new issue has recently come to the forefront of environmental toxicology concerning the possible health hazard from inhalation or ingestion of asbestos fibers. I t has been found that there exists a synergetic effect of a number of organic pollutants when they are associated with asbestos pollution (5,6).In this respect, compounds in tobacco smoke appear to be one of the more active (7). Because of the hypothesis that the toxicity of the asbestos fibers is correlated with the adsorption power of carcinogenic organic pollutants or precursors of carcinogenic compounds (8,9), the intention of our asbestos research work is to characterize the fiber surface (10-15). In this paper we report the results of an investigation on a particular case of organic surface contamination of standard asbestos fibers which was mentioned in a previous article in this journal (1I ) . The characteristic contamination phenom-
EXPERIMENTAL SECTION Apparatus. The commercially available laser microprobe mass analyzer (LAMMA) (LAMMA-500, Leybold-Heraeus, Cologne, Germany) is described in detail in the literature (16-19). The primary advantage claimed for the LAMMA instrument is its ability to analyze very rapidly and with high sensitivity both organic and inorganic species present in a microscopic region of a sample. A variable ionization source in either positive or negative ion detection modes provides sensitive elemental and molecular information (18,19). Asbestos fibers can be held onto a Formvar f i i fixed to a standard copper electron microscope grid. Organic impurities adsorbed onto the surface of asbestos fibers can be detected at low laser irradiance, in the laser desorption (LD)mode (10-12,20-22). For details on sample preparation for LAMMA analysis we refer to De Waele et al. (11). All gas-liquid chromatographic(GLC) analyses were performed with a Hewlett-Packard, Model 3380 A, gas chromatograph, equipped with a flame ionization detector (FID). The data were collected by a H-P 3380 A integrator. A glass column packed with 3% OV-225 on 80/100 mesh Chromosorb WHP was used for the quantitative analysis. The gas chromatographicconditions were as follows: injector temperature, 300 "C; FID detector temperature, 350 "C; carrier gas, argon at 30 mL min-l; isotherm temperature adjustment for DEP analysis, 160 OC, internal standard C&38, and for DOP analysis, 250 O C , internal standard C,,Hw The GC/MS analyses were performed with a Hewlett-Packard 5990-A GC/MS instrument using a glass column packed with
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0 1983 American Chemical Society
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ANALYTICAL CHEMISTRY, VOL. 55, NO. 14, DECEMBER 1983
Dexsil300 GC on 100/120 mesh Chromosorb WHP. The conditions were as follows: injector temperature, 275 "C; programmed-temperature GC, 150-240 "C at 3 "C m i d ; carrier gas, argon at flow rate 25 mL m i d ; electron multiplier voltage, 2200 V. Materials. The asbestos standard fiber samples studied (amosite and crocidolite from Transvaal, South Africa) were supplied by the U.1,C.C. (Union Internationale Contre le Cancer), who has sponsored the preparation and distribution of standard reference asbestos samples (23-26). Polyethylene plastic foil with a known additive composition (375 ppm BHT (butylated hydroxytoluene),550 ppm erucylamide and 450 ppm silica) was supplied by Essochem Plastics, Belgium. Reagents. Benzene (99+% , spectrophotometric grade, Gold Label), n-octadecane (97%),n-dotriacontane (97%),benzo[a]pyrene (99+ %, Gold Label), dimethyl phthalate (DMP) (99%), diethyl phthalate (DEP) (99%),dibutyl phthalate (DBP) (99%), di-2-ethylhexylphthalate (DOP, dioctyl phthalate) (99%),were purchased from Janssen Chimica (Belgium). Octadecyl3-(3,5di-tert-buty-4-hydroxypheny1)propionate (Irganox 1076) (99%), 4,4'-thiobis(6-tert-butyl-m-cresol)(assigned as TBMC) (99%), pentanetetrayl3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (Irganox 1010) (99% ), 1,3,5-trimethyl-2,4,6-tris( 3,5-di-tert-butyl-4-hydroxybenzy1)benzene(Irganox 1330 or Ionox 330) (99%), dilauryl thiodipropionate (Irganox PX 800)) thiodiethyl 3-(3,5di-tert-butyl-4-hydroxypheny1)propionate (Irganox 1035) (99%), 1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl) butane (Topanol CA) (99%))distearyl thiodipropionate(Irganox PS 802) (99%), were obtained from and 2,6-di-tert-butyl-4-n-butylphenol(99%) Ciba-Geigy (Switzerland). 2,6-Di-tert-butyl-4-methylphenol (BHT, butylated hydroxytoluene) (99%) was purchased from Essochem Plastics (Belgium). Benzyl butyl phthalate (BBP) (zw Synthese) and didodecyl phthalate (DDP) (99%)were obtained from Merck (FRG) and Eastman Kodak (Rochester,NY), respectively.
RESULTS AND DISCUSSION In previous work it was shown that the use of laser desorption operating conditions (10-15) in LAMMA results in the ready detection of adsorbed organic constituents. Benzidine, N,N-dimethylaniline (DMA), and benzo[a]pyrene (BaP) were adsorbed in the laboratory on the U.I.C.C. standard samples from liquid solutions and could be readily detected when they were present at a concentration of ca. 500 ppm (11). Catalytically formed oxidation products could be detected when DMA was adsorbed. In one particular experiment, BaP was adsorbed by a gas-phase adsorption process (27,28) on U.I.C.C. crocidolite asbestos. In this case an inhomogeneous distribution of the polyaromatic hydrocarbon was obtained, with only 25% of the fibers analyzed resultivg in the detection of the BaP molecular ion peak at mle 252 (Figure 1A). In the other fibers the presence of an organic surface contaminant with the positive LD mass spectrum shown in Figure 1B was systematically detected though with a variable intensity ratio of the most intense spectral features at mle 360 and 376. We suspected that the organic contaminants which appeared to inhibit further adsorption of BaP resulted from a contamination from the plastic bag in which the material had been stored. The mass spectral components detectable in the positive mass spectrum (mle 332,348,360, and 376) do not provide sufficient information for the identification of the particular compound present. Separate experiments in which a pure crocidolite standard sample was stored in closed polyethylene bags of the same origin as the one used for the adsorption experiment proved conclusively that the origin of the contamination resided in the plastic. It has been reported previously that the U.I.C.C. asbestos standards are often contaminated by storage in polyethylene bags (29-32). Bulk analysis has indicated presence of 3,3',5,5'-tetra-tert-butyldibenzoquinone (molecular mass 408) on the U.I.C.C. crocidolite and chrysotile samples, resulting from the presence of antioxidants in the polyethylene packing
50
1M)
150
I
,
203
250
#
!
I
300 350 400 rnie
Figure 1. Typical positive laser desorption (LD) spectra of gas-phase benzo[a]pyrene (BaP) doped crocidolite: !3aPcontaining fiber (A): fiber containing an accidental surface impurity (B).
material (30). The product was reported to be a catalytically formed oxidation product of the commonly used antioxidant BHT (2,6-di-tert-butyl-4-methylphenol). Qualitative Analysis. The Behavior of Different Antioxidants on Amosite and Crocidolite. In order to check the presence of the particular contaminant detected by Commins and Gibbs (30) in our samples, the adsorption of BHT on crocidolite and amosite was studied from a 0.1 N benzene solution and by an intentionally provoked contamination of the solid asbestos fibers with BHT containing polyethylene. LD mass spectra of the pure compound could not be recorded as it rapidly undergoes sublimation in the vacuum of the mass spectrometer (lo4 Pa). Neither the compound nor its oxidation products could be detected on the asbestos samples. As gas chromatography did not allow detection of any organic impurity in the asbestos samples after prolonged Soxhlet extraction with benzene, we concluded that BHT does not significantly adsorb. Irganox 1076 (octadecyl 3-(3,5-di-tert-butyl-4-hydroxypheno1)propionate)and TBMC (4,4'-thiobis-(6-tert-butyl-mcresol)), two other commercially available antioxidants were also adsorbed from a 0.1 M benzene solution on standard amosite and crocidolite fibers and investigated carefully for possible adsorption characteristics. We selected amosite in addition to crocidolite, as in previous experiments the adsorption capacity and catalytical oxidation reactivity appeared to be more pronounced for this asbestos variety (11). Figure 2A,B shows characteristic examples of a negative and positive mass spectrum of pure Irganox 1076. Both spectra, collected at high laser energy (respectively, 14.5 and 5.1 pJ), provide an intense fragmentation pattern, and the intensity of mass peaks around the molecular mass (mle 530) is very low. The positive mass spectra of the 0.1 M Irganox 1076 doped amosite fibers do not in general show the molecular fragmentation peaks around mle 219 nor the molecular ion at mle 530. Only in extreme laser desorption conditionsfaint signals around mle 219 become apparent (Figure 2C). Analogous results were obtained for crocidolite. These observations indicate that in spite of the high concentrationused in the adsorption experiment, this antioxidant does not show significant adsorption on the fiber surface. It is to be noted that when used at similar concentrations other organic compounds, e.g., polyaromatic hydrocarbons, are very well adsorbed (11). Figure 3 shows typical examples of a negative and positive mass spectrum of pure TBMC. Although the intensity of the
ANALYTICAL CHEMISTRY, VOL. 55, NO. 14, DECEMBER 1983 2257
@ 14.5 pJ
I
I
I
1
I
I
l
l
1
l
1
50 100 150 Mo 250 Mo KO 400 450 Kx) 550 mle Flgure 2. Characteristic negative (A) and positive (B) mass spectrum of pure Irganox 1076 and a positive mass spectrum of an amosite fiber treated with Irganox 1076 from a 0.1 % benzene solution (C). I
r I
I
I
I
0
50
100
150
Flgure 3. Typical negative (A) and positive (B) mass spectrum of pure molecular ion at m / e 358 is much higher than for Irganox 1076, again the adsorption could not be observed for the solution doped amosite fibers. Adsorption experiments were also carried out with amosite using seven other antioxidants in solutions at 0.1 M in benzene, namely, Irganox 1010, Irganox 1035, Irganox 1330,
I
200
I
EO
I
300
I
I
l
l
,
350 400 450 503 550 m/e
4,4'-thiobis(6-tert-butyl-m-cresol)
(TBMS).
Topanol CA, Irganox PS 800, Irganox PS802 and 2,6-ditert-butyl-4-n-butylphenol, none of which show any significant adsorption. Hence, we concluded that the contaminant present in Figure 1B was not caused by antioxidants in the polyethylene plastic bag but rather by another additive. We therefore attempted an identification of the contaminants
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Table I. Mass Spectral Components Detected in Positive LD Mass Spectra of Crocidolite Treated with 0.25 M Benzene Solutions of Several Phthalates qualitative intensity scale (fragment mass) in positive LD spectra
positive ion peaks M t Na M - R t 2Na M - CH,R t 2Na M - CH,R t Na t H M - 2R t 3Na
DMP
DEP
DBP
mol wt 194 R = methyl
mol wt 222 R = ethyl t + t (245) + t (239)
mol wt 278
t t t (217) -
( m / e 233)
M - 2R
t 2Na t H
-
-
t
-
+
+
-
+
+
.1
( m l e 211)
M - 2R -!r Na 4-2H .1
( m / e 189)
M - 2R t 3H
.1
DOP mol wt 390
DDP
mol wt 312 mol wt 502 R= R = butyl R = butyl or benzyl 2-ethylhexyl R = dodecyl + t t (301) + + + (335) + t + (413) + t + (525) t t (267) t (301), + t (267) tt (323) tt (379) t t (309) t (287)
-
.1
BBP
+
t
t
-
t
-
t
t
+
+
t
+
(mle 167) present in the contaminated crocidolite sample. Analysis of the Plastic-Contaminated Crocidolite Sample. A Soxhlet extraction in benzene was made from the original contaminated crocidolite sample. The extract was concentrated through a room temperature evaporation under N2 bubbling through the solution and analyzed with GC/MS. The mass chromatograph at m / e 149 shows the presence of three specific products which can only be assigned to a characteristic rearrangement ion of dialkyl phthalate esters (33). An identical GC/MS analysis on a benzene extract of the pure U.I.C.C. standards did not show the characteristic phthalate peaks. We hence concluded that phthalate ester plasticizers (34-36) were responsible for the fiber contamination. In order to check the adsorption behavior of U.I.C.C. crocidolite fibers for typical phthalate esters, we subjected different portions of crocidolite standard samples to a treatment with 0.25 M DMP, DEP, DBP, BBP, DOP, and DDP benzene solutions. The abbreviations correspond to the full names given in the reagent section. Table I summarizes the predominant fragmentation and molecular ion peaks detected in the positive mass spectra of the doped crocidolite samples and Figure 4 shows representative positive spectra. In contrast with the results obtained for the antioxidants, the phthalate esters show significant adsorption. In the positive LD spectra, the plasticizers show prominent cationized molecular ions (M + Na)+ when adsorbed onto the Na-rich crocidolite asbestos fibers, but also less intense cationized fragmentation peaks can be observed. Cationization has been reported frequently in the literature for organic compounds in an alkali-rich medium (20-22). Spectra of similarly treated amosite samples which contain a considerably lower Na concentration (0.08% compared to 4.4%) (37) show a much lower abundance of the cationized species. As follows from Table I and Figure 4b, DOP shows a somewhat different fragmentation than the other compounds through the loss of a CHzR (R = 2-ethylhexyl) group. It appears that the positive LD spectra allow the ready detection of the different phthalates on the surface of individual crocidolite fibers. The negative spectra on the other hand do not provide significant information on the adsorbed products. However, none of the phthalates used provide a mass spectrum which corresponds to the contaminated sample of Figure 1B. A benzene extract of the contaminated sample was therefore brought in contact with a clean U.I.C.C. crocidolite standard sample.
-I
I
0 44yJ
;
I
50
1W
1%
200
2%
30 350 4W 450 5w 5% mle
Figure 4. CharacteriStic positive LD mass spectra of benzyl butyl phthalate (BBP) (A), di-2-ethylhexyl phthalate (DOP) (B), and didodecyl
phthalate (DDP)(C) adsorbed onto crocidolite fibers. This intentionally contaminated sample provides the positive LD spectrum shown in Figure 5A,B. A representative spectrum made in similar instrumental conditions of the original sample contaminated in the plastic bag is shown for comparison in Figure 5C. The LD spectrum in Figure 5A shows a prominent peak at m l e 413, which indicates the presence of DOP (Figure 4B). In addition, the spectrum of Figure 5B, obtained at slightly higher laser irradiance, contains three of the abundant spectral components of the crocidolite sample contaminated with DOP (Figure 4B and Table I). The differences in the fingerprint mass spectra of Figure 4B and Figure 5A,B can be accounted for by the increased fragmentation with laser irradiance. The identification of the contaminant in Figure 5B with DOP is strenghtened by the appearence of other specific ions at m l e = 135 and 157. With all this information it can be concluded that DOP is the prominent contaminant in the original plastic stored
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Table 11. Concentration of Phthalates on Amosite and Crocidolite after Adsorption from Benzene Solution concn, mg g-' ~
diethyl phthalate (DEP) amosite crocidolite
concn, M
5.2 4.2 0.46 0.42
13.0 7.4 0.54 0.43
0.0100 0.0050 0.0010 0.0005
di-2-ethy1hexy1phthalate (DOPI amosite crocidolite 10.8 2.9 1.0 0.81
4.9 1.0 0.52 0.41
cationized molecular ion intens (re1 scale) crocidolite 39 * 6 27 * 4 17 k 5 0.6 * 0.2
Flgure 6. Characteristic positlve mass spectrum of a crocidolite fiber containing different phthalate plasticizers through storing in a polyethylene bag.
resulted in a concentration of 0.11 mg 8'. These data, although dependent on the experimental conditions, illustrate the considerable adsorption capacity of phthalates on asbestos fiber samples.
CONCLUSIONS
150
200
250
3w
v
350
LW mie
Figure 5. Typical positive LD mass spectra of a crocidolite fiber surface treated with the benzene extract of the original piastic-contaminated fibers at low (A) and high (B) laser energy and of a plaStic-stored crocidolite fiber containing DOP as an organic surface contaminant (C).
sample. Indeed, Figure 5C and Figure 1B indicate the presence of its cationized molecular ion peak at m / e 413 and the molecular ion at m / e 390. However, the cationized fragmentation peaks are absent in these spectra. We postulate that the differences in the adsorption process, through diffusion from the solid plastic packing material and adsorption from the solution phase, result in the difference in mass spectral behavior. The fragments at mle 376,360,348, and 278 have been tentatively assigned as shown in Figure 5C following the general systematics which appeared in the positive spectra of other organic compounds. Quantitative Analysis. The question remains at what concentration levels DOP is present in the asbestos samples in all these accidental and provoked contaminations. Analysis by gas-liquid chromatography (GLC) provided the data summarized in Table I1 for a number of benzene adsorption experiments with DEP and DOP. Both asbestos varieties show a pronounced adsorption from benzene solutions but only for crocidolite was LD mass spectrometry successful in its detection capability. The intensity of the cationized molecular ions in the positive LAMMA spectra is also shown in Table I1 for DOP and crocidolite. It appears that the intensity is not linearly correlated with the amount of organic matter present at the fiber surface. The crocidolite stored in polyethylene bags was also analyzed by GLC. Two samples, with and without an amount of -600 ppm BaP adsorbed from the gas phase, were stored for 380 days in closed bags. They provided a bulk concentration of respectively 0.73 mg and 3.1 mg DOP per gram of asbestos. The storage of the standard fibers during one day
Table I1 shows that the average reproducibility of characteristic cationized molecular ion peaks in the positive mass spectra amounts to of the order of 20% and that surface contamination levels corresponding with a bulk concentration of 500 pg g-' can be safely detected. The detection limit from these, and other experiments can be postulated to be around 100 pg g-l for a repeated series of 10 shots on the same fiber. The reproducibility is considerablybetter than that obtained for organic surface contaminants in other particulate materials, e.g., fly ash. We assume that this is due to the ease with which the laser beam can be focused onto an asbestos fiber. The detection capability is further illustrated in the example shown in Figure 6. The spectrum results from a bulk contamination again at a level of ca. 0.1 mg g-' of crocidolite through storing in a polyethylene bag which contains a mixture of several phthalates, namely, DMP, DBP, BBP, and DOP. All of them are readily and systematically detected. These detection limits correspond to absolute amounts of material of the order of to g. Cationization is a feature which, at least in this phthalate contamination, is of considerable help for the LAMMA detectability. This implies necessarily that detection is worse for other asbestos varieties than crocidolite which contain no sodium as a main constituent. Indeed, the adsorption on amosite fibers is a t least of comparable importance but detection limits are a t least a factor of 10 higher. The cationization and in general the fingerprint mass spectra obtained appeared to be different according to the process which gave rise to the surface contamination. In earlier experiments in which the adsorption of other organic compounds was studied, cationization never appeared to be prominent for crocidolite or the other asbestos types. The results of this example show that until more information is available for the detection and fragmentation behavior of organic constituents, additional information with another technique is necessary for the identification.
ACKNOWLEDGMENT J.K.D.W. is indebted to the "Instituut tot Aanmoediging van het Wetenschappelijk Onderzoek in Nijverheid en
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Landbouw (I.W.O.N.L.)" for financial support. The authors are also thankful to Marcel De Winter (Essochem Plastics, Belgium) and Maurice Leeuwerck (Ciba-Geigy,Belgium) for their invaluable advice and for providing several pure plastic-additive samples, and to Paul Schepens and Jos Janssens (Department of Pharmacy, U.I.A.) for the GC/MS analyses. Registry No. DMP, 131-11-3;DEP, 84-66-2; DBP, 84-74-2; DDP, 2432-90-8; BBP, 85-68-7; DOP, 117-81-7; BaP, 50-32-8; TBMS, 96-69-5;Irganox 1076,2082-79-3;polyethylene, 9002-88-4; crocidolite, 12001-28-4.
LITERATURE CITED (1) Moore, J. A. Proceedings of the Workshop on Asbestos: Definitions and Measurement Methods, Galthersburg, MD, July 18-20, 1977; National Bureau of Standards Special Publication 506, 1977; pp 153-161. (2) Coffin, D. L.; Paiekar, L. D. Proceedings of the Workshop on Asbes-
tos: Definitions and Measurement Methods, Galthersburg, MD, July 18-20. 1977; National Bureau of Standards Special Publlcaton 506, 1977; pp 163-177, (3) IARC Monographs on the Evaluation of Carcinogenic Risk of Chemicals to Man, International Agency for Research on Cancer, Asbestos, 1977: Voi. 14. (4) Elmes, P. C. R. SOC. Health J . 1976, 96, 248-252. (5) Bignon, J.; Blentz, M.; Sebastien, P.; Bonnaud, G. Polluf. Atmos. 1976, 26 (33). 2353-2357. (6) Harington, J. S i Allison, A. C.; Badami, D. V. Adv. Pharmacol. Chemother. 1975, 72,291-402. (7) Seilkoff. I.J.; Hammond, E. C.; Churg, J. JAMA, J . Am. Med. Assoc. 1968. 204 (2). , ~ 104-1 ,- ~ 10. (8) Contour, J. P.; GuBrin, I.; Mouvier. G. Atmos. Pollut. 1978, 7 , 255-259. Proceedings of the 13th International Colloquium, Paris, April 25-28; Benarie, M. M., Ed. "Studies in Environmental Science"; Elsevier: Amsterdam, 1978. (9) Contour, J. P.; GuBrin, I.; Mouvier, 0. Environ. Polluf., Ser. B 1980, 7 , 243-257.
(IO) De Waeie, J. K.; Van Espen, P.; Vansant, E. F.; Adams, F. C. Proceedings of the 17th Annual Conference on Microbeam Analysls, Washington, DC, August 9-13, 1982; Heinrich, K. F. J., Ed.; San Francisco Press Inc.: San Francisco, CA, 1982; pp 371-377. (11) De Waele, J. K.; Vansant, E. F.; Van Espen, P.; Adams, F. C. Anal. Chem. 1983, 55,671-677. (12)
De Waele, J. K.;Verhaert, I.; Vansant, E. F.; Adams, F. C. S I A , Surf.
Interface Anal., In press. (13) De Waeie, J. K.; Adams, F. C. Presented at the 9th Course of the
NATO Internatlonai School of Quantum Electronics on Analytical Laser Spectroscopy, Erice. Italy, September 23-October 2, 1982.
(14) Van Espen, P.; De Waeie, J. K.; Vansant, E. F.; Adams, F. C. Int. J . Mass Spectrom. Ion Phys. 1983, 4 6 , 515-518. (15) Surkyn, P.; De Waele, J. K.; Adams, F. C. Int. J . Environ. Anal. Chem. 1983, 13,257-274. (16) Vogt, H.; Heinen, H. J.; Meier, S.; Wechsung, R. Fresenius' Z . Anal. Chem. 1981, 308, 195-200. (17) Kaufmann, R.; Hiiienkamp, H.; Wechsung, R. Med. Prog. Technol. 1979, 6,109-120. (18) Denoyer, E.; Van Grieken, R.; Adams, F. C.;-Natusch, D. F. Anal. Chem. 1982, 5 4 , 26A-41A. (19) Hercules, D. M.; Day, R. J.; Baiasanmugam, K.; Dang, T. A.; Li, C. P. Anal. Chem. 1982, 5 4 , 280A-305A. (20) Heinen, M. J.; Meier, S.; Vogt, H.; Wechsung, R. Fresenius' 2. Anal. Chem. 1961, 308, 290-296. (21) Busch, K. L.; Unger, S. E.; Vincze, A.; Cooks, R. G.; Keough, T. J . A m . Chem. SOC. 1982, 104, 1507-1511. (22) Baiasanmugam, K.; Dang T.; Day R.; Hercules, D. M. Anal. Chem. 1981, 53, 2296-2298. (23) Timbrell, V.; Rendail, R. E. Powder Technol. 1971/1972, 5 , 279-287. (24) Timbreli, V. Pneumoconlosis, Proceedings of the International Conference, Johannesburg, 1969; pp 28-36. (25) Timbrell, V.; Giison, J. C.; Webster, I. Int. J . Cancer 1968, 3 , 406-408. (26) Timbreli, V. "Biological Effects of Mineral Fibers"; Wagner, J. C., Ed.; IARC Scientific Publicatlons: Lyon, 1980; Voi. 30(1), pp 127-142. (27) Korfmacher, W. A.; Miguel, A. M.; Mamantov, G.; Wehry, E. L.; Natusch, D. F. Environ. Sci. Technol. 1979, 73,1224. (28) Mlguel, A. H.; Natusch, D. F. Anal. Chem. 1975, 4 7 , 1705-1707. (29) Harington, J. S. Ann. N . Y . Acad. Sci. 1965, 732,31-47. (30) Commins, 8. T.; Gibbs, G. W. Br. J . Cancer 1969, 23, 358-362. (31) Hilborn, J.; Thomas, R. S.; Lao, R. C. Sci. Total Environ. 1974, 3 , 129-140. (32) Llmasset, M. J.4.; INRS Revue Bibliographique, note no. 1036-85-76, 1976; pp 559-567. (33) Beynon, J. M.; Saunders, R. A.; Williams, A. E. "The Mass Spectra of Organic Molecules"; Elsevier: Amsterdam, 1968; p 236. (34) Buttrey, D. N. "Plasticizers", 1st ed.; Cleaver-Mume Press Ltd.: London, 1950. (35) Crompton, T. R. "Chemical Analysis of Additives in Plastics", 2nd ed.; Pergamon Press: Oxford, 1977. (36) Hawiey, G. G. "The Condensed Chemical Dictionary", 9th ed.; Van Nostrand Reinhold: New York, 1977; p 891. (37) Rendall, R. E. Pneumoconiosis, Proceedings of the International Conference, Johannesburg, 1969; pp 23-36.
RECEIVED for review June 28,1983. Accepted September 1, 1983. Support for this research was provided by the European Communities (Research Grant ENV-620 B(RS)) and the Interministrial Commission for Science Policy, Belgium (Research Grant 80-85-10).
Characterization of Organic Dyes by Secondary Ion Mass Spectrometry S. M.Scheifers, S. Verma, and R. G. Cooks* Department of Chemistry, Purdue University, West Lafayette, Indiana 47907
The utiilty of secondary ion mass spectrometry (SIMS) for identification of dyes is demonstrated. Abundant molecular ions and structurally diagnostic fragment lons characterize the SIMS spectra of several classes of organic dyes. By examining precharged compounds, one ensures maximum yields of structurally diagnostic Ions. Detection limits for samples supported on metal foils are 10 ng. Direct analysts of dyes from paper chromatogramsglves an unchanged spectrum but higher detection limits, ca. 1 pg. Minimal noise Is introduced when ions are desorbed from the paper support.
Complementary information from various analytical techniques is often required for the unambiguous identification and quantification of organic dyes ( I ) . Not only are a variety of structural types represented but also impurities, including 0003-2700/83/0355-2260$01.50/0
homologous compounds, are often present. Along with optical spectrometry and nuclear magnetic resonance, mass spectrometry (MS) has emerged as a useful tool in the analysis of dyestuffs. Thin-layer chromatography, paper chromatography, and electrophoresis are the most common purification methods employed in conjuction with the above spectroscopic methods. Hence, a desirable feature of mass spectrometric techniques for the analysis of dyes is the ability to analyze directly from chromatographic media. Until the recent development of desorption ionization techniques (2) such as field desorption (3-5) and electrohydrodynamic ionization (6, 7), mass spectrometry was largely confined to the analysis of thermally stable and volatile dyes using electron ionization (EI). Earlier literature on the mass spectrometric analysis of ionic dyes cites examples of the use of chemical reactions such as dequaternization (8) to yield volatile neutral compounds prior to analysis, together with 0 1983 American Chemical Society
