Gschwend%20thesis.pdf

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" CSi was injected with the split closed (K. Grob and K. Grob, Jr., 1974). The split was opened (10: I ratio) after 30 sec. The helium carrier gas flow rate was 3 ml/min at 20°C. The injector and detector were operated at 250°C. The temperature program was: 2Q-.22"C isothermal for 8 min, then 3°C/min to 250°C. GC-MS analyses and structural identifications were performed on a Finnigan Model 3200 equipped with a Data System 600 computer. A Finnigan Model 9500 gas chromatograph equipped with a Finnigan splitless injector and a 25 m x 0.32 mm i.d. glass capilary SE 52 column was interfaced to the MS with an all-glass. transfer line, held at 250°C, allowing coaxial introduction of reagent gases for chemical ionization (CI-MS) (Blum and Richter, 1975, 1977). Mass spectra were recorded at the rate of one per 1. sec from 35 to 350 amu at 70 e V and 90°C source temperature for EI; and at one per 1. sec over a range of 60350 amu at 130 e V and 90°C source temperature for CI. Methane was used as the chemical ionization reagent gas. Compounds were identified by comparison of GC and GC-MS properties with those of authentic standards or library spectra as indicated in Table 2. Method characteristics Blanks. Since most VC in seawater were present below the 10 ng!kg level, much below the levels previously reported for other samples (K. Grob and G. Grob, 1974), a premium was placed on achieving sensitivity and low, reproducible blanks. Figure IA shows a representative gas chromatogram ofthe trap extract from stripping a moist 5 1 flask containing prestripped air. As usual, 40 ng I-chloro-octane (No. 2(0) were added to the trap before extraction and its peak height corresponded to 10 ng!kg in water . usually processed. This typical instrument blank shows quantitative recovery of the standard and the presencè of very few peaks, corresponding to less than . i ng each VC!kg seawater introduced by the stripping . procdure from the apparatus iud by subsequent manipulations. Contamination from laboratory air can erratically be a serious problem. Pouring pre- ~ stripped water from one flask to another in the laboratory introduced numerous contaminants at the 10 ng!kg leveL. However, stripping five liters of 'CD air' (sampled by emptying a flask filled with prestripped water at CD) does not give these laboratory contamination problems. Recovery. TIie. recovery of internal standard~ relative to I-chloro-octane (No. 200) was always above 85%. We restrip all samples immediately after the first strip and again after 24 hr to monitor recovery and compound generation. The internal standards are never detectable in these restrips. Figure IB is typical of additional recovery of VC on restripping a relatively non-turbid water sample after initial strip (Fig. 2C). For most compounds little material above the blank occurs in the rest rip. However, substantial Volatile organic çornpounds in coastal seawater quantities of n-pentadecane (No. 417) and n-heptadecane (No. 515) frequently occur in the second strip, and the yield of dimethyldisulfide (No. 37) and dimethyltrisulfide (No. 149) typically increases, especially after 24 hr (Fig. i C). A few samples that were especially turbid or contained -high total levels of volatiles yielded substantial recoveries on restripping. This is ilustrated in Fig. i D, the restrip of the turbid sample shown in Fig. 2B. The VC concentrations reported in this paper are those recovered in the first 2 hr stripping only. Recovery experiments were also conducted in duplicate using two different strippers, traps and analysts. Different seawater samples were spiked with a test mixture of compounds encompassing a variety of chemiCai functionalities and volatilities within the expected range of the technique, Samples were spiked at 5, 10, 50, and 100 ng of each compound!kg seawater. Acetone solutions of the mixture were used to introduce the spike. The two lower level experiments utilized exhaustively prestripped low-turbidity CD water, whereas the two higher level experiments used untreated CD water of low turbidity. The recovery for each compound was determined by comparing GC peak areas (normalized to I-chloro-octane, No. 200) determined by a Columbia Scientific Instruments "Supergrator 3" electronic integrator for the sample with peak areas from GC analysis of the test mixture. The test mixture composition and the average recoveries are given in Table i. For each compound, the fraction recovered was independent of the level added, suggesting the absence of 'threshold effects' at these levels. The poor recovery of the naphthalenes is entirely due to poor extraction recovery from the charcoal traps (35%) as shown by trap spiking experiments. Although I-octanol is also lost to some extent , on the traps (58% recovery), its extremely poor total , recovery is probably primarily due to its high water solubility. Reproducibilty. In order to assess the reproducibility of sampling, stripping, and analysis as applied to environmental samples, duplicate seawater samples were obtained on five separate occasions and processed concurrently on two different strippers by two different analysts. Precision waS estimated by measuring the heights of twenty of the larger peaks relative to the I-chloro-octane (No. 2(0) peak height. With the few exceptions listed below, these peak height ratios did not vary between duplicates by more than 15%. Peak height ratio differences of up to 30% were shown by dimethyldisulfide (DMDS, No. 37), demethyltrisulfide (DMTS, No. 149), nonanal (No. 225), decanal (No. 275), and n-heptadecane (No. 515). We find that removing salt and other deposits from seawater samples from the charcoal traps by the procedure of Grob and Zürcher (1976) after every few samples maintains good reproducibility. The moderately large headspace over our samples was adopted to minimize the salt spray transport onto the traps. . We have experienced irreversible trap clogging from 95
96 R. P. SCHWARZENBACH. R. H. BROMUND. P. M. GSCHWEND and O. C. ZAFIRIOU I I; 8 JtL )/ l ~ ."' 'i -- J 28 A "INSTRUMENT BLANK" (6/21t711 B RESTIlIP NONTURBID WATER ( 7/\971) ~ " ;; I: u C IlSTRIP B AFTER 24 HOIl (7/19/77) §' ~ ~ I i ~'-- L~ I i ! o RESTRIP TURBID WATER (3124/77) ~ 38 48 TIME (min) 0 8 II 'Æ" C-C I 20 20 .0 80 no .40 "N N Fig. 1. Characteristics of the procdure. Peak No. 200 is the internal standard applied to the trap at the time of extraction and corresponds to 10 ngjk¡ of seawater sample. For peak number identifications refer to Table 2. ...L-,~
Page 1 and 2:
VOLATILE ORGANIC COMPOUNDS IN SEAWA
Page 3 and 4:
-3- concentrations were observed to
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-5- analyses. Joy Geiselman collect
Page 7 and 8:
Approval Page Abstract. . . Acknowl
Page 9 and 10:
Figure 2-1 2-2 2-3 2-4 2-5 2-6 2-7
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-11- 4-5 O-xylene in Vineyard Sound
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-14- background ~ the next two chap
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-16- those at room temperature. On
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-18-. Table l-l. Ha logenated volat
Page 20 and 21:
-zo- They found total n-alkanes (C6
Page 22 and 23:
-2Z- alpha-pinene ( ~ ), and limone
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-24- Land animals also utilize vola
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-26- importance of transport mechan
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-28- Recently, methods have been de
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-30- Figure 2-1. Station locations
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-32- A third set of seawater sample
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-34- These analyses provided a lowe
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'" ~ ~ ~ o 500 TEMPERATURE (OC) 10
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SampIe station/ depth (m) Sargasso
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NOj (PM/kg) o 10 20 30 40 chI a (Pg
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Figure 2-4. -42- o 0 . o Sections s
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-44- Figure 2-5. Sections showing n
Page 46 and 47:
-46- Figure 2-6. Sections showing o
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-48- Figure 2-7. Sections showing i
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-50- and l49 (M+41) ions in the CH4
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~ ~ ~ ~ ii "' ~ ï: "' l¡ Q: 3(' 5
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-54- A family of straight chain ald
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o 10 6 6.0 100 3.2 1000 . 2.2 0 9.2
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-58- Equatorial Atlantic, does not
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-60- Zsolnay (l973, 1976) has repor
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netS 40 (ng/kg) 20 +24/7 +15/7 30 2
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sample was enriched relative to adj
Page 67 and 68:
-67- On the other hand, a phytoplan
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°2 (m//kg) 2 6 . . . . 4 . . . . .
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-71- Figure 2-13. Mechanism for pro
Page 73 and 74:
-73- fatty acid, hexadecanoic acid,
Page 75 and 76:
-75- In addition, the Cape, and the
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::.',:.:' 71° 70° 69° 68° 67°W
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-79- Figure 3-2. Recirculating stri
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-81- o (heated to 60 C to reduce th
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VOLATILE EXTRACTION ref. Grab and Z
Page 85 and 86:
RESULTS AND DISCUSSION Hydrographic
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-88- Figure 3-5. Salinity (0/00) ve
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-90- revealing the variation of sal
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.. 1.5 ..E0 1.0 - Ci ci :: 0.5 II'
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-94- Figure 3-7. Chlorophyll ~ (~g/
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-96- Three known incidents of hydro
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~ ( ng/kg) 40 30 20 ._... ~ ? 1 0 .
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~ 4 2 ( ng/kg) o '-+~ ( ng/kg) ~ (
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o to o (\ . -. /..., ., --. o .. (a
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-104- Figure 3-11. O-xylene concent
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-106- Figure 3-12. Electron impact
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-108- (Müller and Jaenicke, 1973).
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30 20 UNKNOWN m.w. 108 10 (ng/kg) o
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-112- Figure 3-14. Naphthalene and
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-114- The naphthalene-to-methyl nap
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-117- with 0.29 for o-xylene and 0.
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nC14 15 10 (ng/kg) 5 o 80 60 n C 15
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"ep¡" 50 40 30 20 10 s...." . . \~
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-123- Figure 3-18. C6-CiO aldehyde
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Figure 3-19. -125- Heptanal concent
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-127- production by the plankton or
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20 18 2 16 ~ "- 14 3 3 3 :- 12 3/ 2
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tf 10-' ~ ~ ct ~ ~ ~ ~ '" .. ~ ~ ~
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15 DMDS (ng/kg) 5 o 35 30 25 DMTS 2
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-135- polysulfide volatiles. Partic
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TOTAL VC (ng/kg) 500 400 300 200 10
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-139- This suggested an anthropogen
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"Also, short range transport and de
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-143- were conducted. Rain samples
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Short-term Temporal Studies. -145-
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40r RAIN RAIN 124 ~ 0 \ . MORNING (
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-149- Figure 4-2. Relative C2- and
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-151- Finally, the diesel-exhause-d
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Figure 4-3. Ratios of C2- and sampl
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Figure 4-4. Salini ty CD taken velo
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-157- Figure 4-5. O-xylene concentr
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-l59- while at other times they wer
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CDsw CDsw 11/10/77 11/22/77 CDsw 10
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-163- Figure 4-6. a-xylene concentr
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-165- The Quashnet River and Sippew
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Sippewissett Quashnet CD Marsh CD C
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r . I , , I . . I · ~_. . . TEMP .
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DATE AIR MEASUREMENTS -171- o-xylen
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-173- but that direct inputs (e.g.
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-175- an atmospheric source did not
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Table 5-1. Date of collection colle
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-179- gas chromatograph equipped wi
Page 181 and 182: -181- UCON R1 Compound SE54 R1 HB51
Page 183 and 184: Release rates (ng/gm dry weight/day
Page 186 and 187: - l86- are shown in parenthese s. T
Page 188 and 189: -l88- June and September, it may be
Page 190 and 191: -190- study in some summer samples
Page 192 and 193: -192- Surprisingly, the Rhodophyta
Page 194 and 195: -194- Three deep samples (ca. 2000m
Page 196 and 197: -196- indicated that these hydrocar
Page 198 and 199: -l98- average year-round sample dat
Page 200 and 201: -200- hydrogens of the C2- and C3-b
Page 202 and 203: -202- Application of sensitive sele
Page 204 and 205: -204- tubing into round bottom flas
Page 206 and 207: -206- Figure I-I. Stripper used wit
Page 208 and 209: -208- sample. Sample water was forc
Page 210 and 211: -ZIO- ionization spectra were acqui
Page 212 and 213: . . TEMP BLAN K BEFORE SAMPLE 10m 2
Page 214 and 215: -214- Table I-i. Recoveries (%) of
Page 216 and 217: -2l6- Table 1-2. Standard deviation
Page 218 and 219: Grob Methodology -2l8- The methods
Page 220 and 221: -220- compound m & p xylenes mw 108
Page 222 and 223: -222- Table 1-4. Recoveries (ng/kg)
Page 224 and 225: -224- purchased them. Tenax may be
Page 226 and 227: -226- Appendix II. Hydrographic dat
Page 229 and 230: -229- Appendix III. Volatile organi
Page 231: 94 R. P. SCHWARZENBACH, R. H. BROMU
Page 235 and 236: 98 R. P. SCHWARZENBACH, R. H. BROMU
Page 237 and 238: 100 R. P. SCHWARZENBACH, R. H. BRoM
Page 239 and 240: 102 R. P. SCHWARZENBACH, R. H. BROM
Page 241 and 242: 104 Oxygeii compouiids R. P. SCHWAR
Page 243 and 244: 106 R. P. SCHWAKZENRACH. R. H. BROM
Page 245 and 246: -245- Appendix iv. Physical chemica
Page 247 and 248: -247- Appendix V. Mass spectra of s
Page 249 and 250: IS N L~ N r IS N ~Ð :i ,E -i Ji: "
Page 251 and 252: LD~ E) E) (Y E) LD E) LD N X E) in
Page 253 and 254: il .. E) N X I E) E) (Y E) il N E)
Page 255 and 256: CD CD .. r. L. - N ~-'._-----'-----
Page 257 and 258: E) i N f f ( -455 .- N ~ r t ì igN
Page 259 and 260: E) E) ~i !D i N --- J -lri r~ 18 r~
Page 261 and 262: REFERENCES Ackman, R.G., C. S. Toch
Page 263 and 264: . Cleveland, W. S., B. air pollutio
Page 265 and 266: -264- Grob, K. and F. ZUrcher. (l97
Page 267 and 268: -266- Lee, C. and J.L. Bada. (1975)
Page 269 and 270: -268- N. A. S. (1975a) Assessing Po
Page 271 and 272: -270- Strickland, J.D .R. and T .R.
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