Carbohydrates from Santa Barbara Basin sediments: Gas chromatographic-mass spectrometric analysis of trimethylsilyl derivatives

Qeochimica et Coamochimica Acts,1071,Vol.35, pp. 825 to 838. Pergamon Press. Printed in Northern Ireland

Carbohydratesfrom Santa Barbara Basin sediments: Gas chromatographic-massspectrometric analysis of trimethylsilyl derivatives JUDITH

E. MODZELESKI*,

WILLIAM

A.

LAIJRIE~$

and BARTHOLOME w NAGY * The University of Arizona, Tucson, Arizona 85721 (Received

27 October

1970;accepted in revised form 25 March 1971)

Santa Barbara Basin marine sediments were hydrolyzed and the concentration and identification of their constituent carbohydrate moieties were determined. The ages of these sediments were estimated to be ~60 yr and ~750 yr, respectively, by counting seasonal varves by X-ray techniques. Thin-layer chromatograms developed in ethyl acetate, pyridine and water or in n-propanol, ethyl acetate and water indicated the major constituents of the desalted hydrolysates. Combined capillary gas chromatography-mass spectrometry of trimethylsilyl (TMS) derivatives of the hydrolysates resulted in the identification of glucose, galactose, mannose, ribose, xylose, arabinose, fucose and rhamnose, as well as mannitol and the TMS derivatives of stearic and palmitio acids. The two marine sediments contained the same carbohydrate moieties with a lower total concentration in the -750-yr sample; some of the sugars seem to be similar to those commonly found in marine algae. The total organic content of the two sediments was approximately the same.

Abstract--Two

CARBOHYDRATEShave been described from Recent marine and lacustrine sediments, peat, sedimentary rocks, and soils (e.g. THEANDER, 1954; VALLENTYNE and BIDWELL, 1956; PLUNKETT, 1957; SWAIN, 1958; PALACAS et al., 1959, 1960; PRASHNOWSKY et al., 1961; RITTENBERG et al., 1963; ERDMAN, 1964; KROEPELIN, 1964; ROGERS, 1965; SWAIN and ROGERS, 1966; SWAIN et al., 1967a,b; SWAIN et al., 1969). The occurrence of carbohydrates in rocks and sediments is of interest because they may have a role as indicators of environmental conditions during deposition and possibly during diagenesis. It has been considered by some investigators that carbohydrates would not readily survive long in many sedimentary The introduction of thin-layer chromatography to carbohydrate environments. analysis during the past few years, as well as combined gas chromatography-mass spectrometry for the identification of volatile carbohydrate derivatives, offers powerful and reliable analytical microtechniques to study carbohydrate geochemistry. This study was undertaken to determine the feasibility of adapting these microtechniques to the analysis of carbohydrates in marine sediments and to study the relative molecular composition of carbohydrates in marine sediments of different ages but of the same environment. Such a study can conceivably indicate some of the types of organisms which lived and contributed to the sugar content of the sediment at the time of deposition. * Department of Geosciences, t Department of Chemistry $ Present address: The Rockefeller University, New York, New York 10021. 825

826

J. E. MODZELZSEI, W. A. LAURIEand B. NAGY EXPERIMENTALPROCEDURESAND RESULTS

Two marine sediment samples, both collected from the Santa Barbara Basin, were analyzed for their content of bound sugars. The &at sample, estimated to be 50 ( f 10) yr, was frozen immediately after collection and was dated by an X-ray technique which permitted counting the seasonal varves (SOUTAR,1970); the second sample was collected and dated in an identical manner and was found to be approximately 750 ( & 50) yr. The location of the first sediment was 34”17’N, 120”08’W and of the second sample, 34”16.2’N, 120”03’W. The depth of water at the sample sites was 570 to 580 meters; the depth of the - 50-yr sediment was N 35 cm below the water-mud interface; the depth of the - 750-yr sediment was - 160 cm below the water-mud interface. Chemical extractions and acid hydrolysis

This study was concerned only with bound sugars, either those which are organically bound polymers, such as polysaccharides, or with those which might possibly be adsorbed or bound by a partially ionic bond to clay minerals present in the sediments. It was considered that aqueous solutions of free sugars may percolate through the Recent sediments and, consequently, may be younger than the sediment itself. For this reason free sugars were not analyzed. In order to minimize contaminations from free sugars, the frozen sediments were washed exhaustively with distilled water and freeze-dried for storage. To prevent any moisture from collecting, the freeze-dried sediments were stored over indicating silica gel and checked periodically for any sign of moisture accumulation. None was observed during the course of the work. Prior to hydrolysis of the sediment, a 2-g sample was washed 6-10 times with 25 ml of triple distilled water, centrifuged, and the supernatant solutions removed. This procedure removed water-soluble colored material which could have interfered with subsequent analyses, and also all remaining free sugars and water-soluble polysaccharides not bound in the sediment. The centrifugation residue was then dried under a stream of N, (filtered through molecular sieve pellets), followed by solvent extraction (6-10 times) with a CHCl,:MeOH (1:l v/v) solution (NAQY et al., 1965) for 30 min at 65°C with constant stirring to remove pigments. The supernatant solutions were collected after centrifugation. Following removal of the residual CHCI,:MeOH by evaporation under N,, the sediment was hydrolyzed with 11 ml of 2N H&SO, (STACEY and BARKER, 1960) for 90 min at 100°C. The supernatant acid solution was collected and the sediment rehydrolyzed with an additional 11 ml of acid for 60 min. The combined supernatant acid solutions plus five water washes (25 ml) were neutralized to a pH of 4 to 4.5 with sat. Ba(OH), (VOLCANI, 1970). The resulting hydrolysate was concentrated, brought up to a known volume (25 ml) in water and analyzed for total sugar by the phenol-sulfuric acid method (DUBOISet al., 1956). Total sugar (based on dry weight) was: (1) - 50 yr = O*6o/o( & O*O5o/o); (2) N 750 yr = 0.3% ( & O*O5o/o).A visible spectrum (350-550 mp) was taken on both sediment hydrolysates and showed maxima at 483-483.5 mp. Since the maximum absorption for hexoses in the phenol-sulfuric method is 490 my and that of pentoses and/or 6-deoxyhexoses is 480 rnp, the absorption at 483 to 483.5 m,u is indicative

Carbohydrates

from Santa Barbara

basin sediments

827

of a nearly equimolar mixture of pentoses and/or 6-deoxyhexoses and hexoses. Total organic content of both sediments was determined. This value was based upon conversion of the organic material to CO, at a sufficiently low ignition temperature so that it did not affect carbonates, as was shown by controls. The N 750-yr sediment was found to contain a total organic content of 12.3 per cent and the N 50-yr sample had a total organic content of 11.6 per cent. Preparative

desalting

Prior to thin-layer chromatography, it wss necessary to desalt the hydrolysates and thereby allow free mobility of the individual sugars on the plates. Desalting was accomplished by using mixed resins, Bio Rad AG 3 x 4, Cl- and Bio Rex 40, H+, 2:1, v/v (SMITH, 1960). The resins (50:25 ml, v/v) plus the hydrolysate (from 2 g of sediment) were placed in a flask and constantly stirred for 2 hr at room temperature. After removal of the resins by filtration and concentration of the samples, the desalted hyrolysate was again analyzed by the phenol-sulfuric method. The analysis showed a net weight loss of sugars after desalting of 24 per cent. The visible spectrum on the desalted hydrolysate, however, showed no change in absorption bands and the loss of sugar was considered to be largely non-selective; the exception being that any uranic acids or amino sugars present in the hydrolysate before desalting would be retained on the resins. Thin-layer

chromatography

Commercially prepared sheets of cellulose on aluminum foil (Brinkman Co.) were used and development was carried out in a sandwich type flat chamber. The multiple ascending technique (3x), used commonly in paper chromatography of sugars, was employed. The solvent systems (Tables 1 and 2) were miscible and were prepared fresh daily. All thin-layer sheets were prewashed prior to application of a sugar sample. The solvent front was 10 cm. Detection was with 0.1 M p-anisidine phthalate in 95% EtOH. The plates were sprayed, allowed to air dry and then bested at lOO-105°C for 5 min (RANDERATH,1966). The sensitivity of this spray was 3.5 ,ug for each standard sugar. Table 1. Thin-layer

chromatography

R, standard sugars

sugars

Glucose Galactose Mannose Arabinose Xylose-Fucose Ribose Rhamnose unknown Solvent system I

(PROCEAZEA,

0.36 0.40 0.44 0.47 0.51 0.58 0.61 1961)-Ethyl

Rr N 60 yr sediment

Rf - 760yr

0.36 0.40 0.44 0.47 0.61 0.57 0.62 0.68 Acetate/Pyridine/H,O

sediment 0.37 0.40 0.44 0.47 0.51 0.69 0.62 0.68 (10:4: 3, v/v/v).

828

J. E. MODZELESKI,W. A. LAURIE and B. NAGY Table 2. Thin-layer chromatography Sugars Glucose Galactose MEI.MOSO

Arabinose Xylose Fucose Ribose Rhamnose Unknown

R, standard

R, - 50 yr

R, -750 yr

sugars

sediment

sediment

0.40 0.43 0.47 0.50 0.53 0.56 0.59 0.65 -

0.40 0.43 0.48 0.50 0.53 0.56 0.59 0.65 0.76

0.41 0.43 0.48 0.50 0.53 0.56 0.59 0.65 0.76

Solvent system II (BLOCK et al., 1958)-n-Propanol/Pyridine/HsO

(7 : 1: 2, v/v/v).

The hydrolysates were also checked for the presence of ketoses by spraying with 0.2% naphtholresorcinol in orthophosphoric acid (RANDERATH, 1966). The characteristic red spot denoting ketoses was absent in both hydrolysates. The most intense individual sugar spot was xylose. An unknown, occurring in trace amounts above rhamnose, is thought to be a lactone sugar which was probably formed from uranic acids during the desalting procedure (STANEK et al., 1963) Gas chromatography-mass

spectrometry

In order to perform gas chromatographic analyses of the hydrolysates, it was necessary to convert the sugars to volatile derivatives. Trimethylsilyl (TMS) derivatives were chosen because of their relative ease of formation and thermal stability (SWEELEY et al., 1963). Pierce Chemical Company’s commercial “TriSil” reagent, prepared in 1 ml ampoules, was used for all standard sugar silylations. The 1 ml mixture of hexamethyl-disilizane (HMDS) and trimethylchlorosilane (TMCS) in dry pyridine was added to a vial containing 44 mg of dry sugars. After standing at room temperature for 24 hr, the excess silylation reagents and pyridine were removed under a stream of dry N, and the silylated sugars were dissolved in freshly redistilled hexane. The precipitate formed during silylation (presumably NH&X) was removed by centrifugation. It was found that the procedure used for standard sugars was not fully effective for the hydrolysates. The yield of silylated sugars was only about 10 per cent of the expected value. It is possible that colloidal-sized clay particles with active sites were present and competing with the sugars for the silylating reagents. The silylation procedure was, therefore, modified as follows: the hydrolysate containing 10 mg of total sugars was first filtered through a 0.22 ,u pore size Millipore filter and then dried. Pierce’s “Tri-Sil” concentrate, containing HMDS and TMCS without pyridine, was used for silylation; the “Tri-Sil” concentrate (0.75 ml) was mixed with dry pyridine (2.5 ml) and 2-O ml of this solution was added to the dry sugar hydrolysate. Silylation was allowed to proceed for 24 hr and the products were then treated as were the standard sugars. An open tubular capillary column (0.02 in. x 150 ft) coated with SE-30 was used for the gas chromatography of both the sugar standards and the hydrolysates.

Carbohydrates from Santa Barbara basin sediments

829

A Perk&Elmer 226 Gas Chromatograph connected directly to a Hitachi RMU-6E Mass Spectrometer via a Watson-Biemann molecular separator was used for the analyses. Helium, at a flow rate of 4 cmS/min was used as the carrier gas and a H, flame detector was employed. The injection port temperature was 190°C. Since SE-30 separates the u and /? anomers of the various sugars (KXRKKXINEN et al., 1966; PIERCE, 1968), all sugar solutions were well-equilibrated aqueous solutions in which mutarotation had occurred. Silylation of such solutions seems to proceed without changing the original cc and #?composition (SWEELEY et al., 1963). A

STANDARD SUGARS TRIMETHYLSILYL DERIVATIVES

ATTEN --7

250”

250”

220”

I tMPtRAl%?E

190”

160”

I504

(“Cl ---tc075”/MIN

+lSOTHERMAL---rc75”/MIN PROGRAM

IO

--+

RATES

Fig. 1. Gas chromatogram of the standard sugars. TMS derivatives of: (1) arabinose, (2) rhamnose, (3) arabinose, (4) ribose, (5) fucose, (6) rhamnose, (7) fucose and xylose, (8) xylose, (9) mannose, (10) galactose, (11) a-D glucose, (12) mannose and galactosa, (13) /?-D glucose.

A O-4 ,ul volume containing 200-250 pug of standard sugars was injected onto the column and peak identities were established by co-injection of the individual sugars. For the hydrolysates, a 0.6 ,ul volume was injected representing approximately 300 rugof total sugars. A standard sugar sample containing eight silylated sugars resulted in thirteen major peaks (Fig. 1). The thirteen major peaks from the eight known sugars were present in each hydrolysate in addition to three unknown peaks (peaks 9, 14 and 16; Figs. 2 and 3). Both hydrolysates showed basically the same gas chromatographic pattern. Mass spectra were taken of all major components as they entered the mass spectrometer and were compared to the spectra of standard TMS sugars from the gas chromatographic runs. The SE-30 column had a low bleed rate and spectra

J. E. MODZICLESEI,W. A.

830

B

and D.

LURIE

NAUY

~50 YRS SEDIMENT HYDROLYSATE, TRIMETHYLSILY~ DERIVATIVES.

Fig. 2. Gas chromatogram of sugars from the -50 yr sediment. TMS derivatives of:

(1) arabinose, (2) rhamnose, (3) arabinose, (4) ribose, (5) fucose, (6) rhamnose, (7) fucose and xylose, (8) xylose, (9) a pyranose hexose, (10) mannose, (11) galactose, (12) X-D glucose, (13) mannose and galactose, (14) mannitol, (I 5) 8-D glucose and palmitic acid, (16) steario acid, (17)-(20) unsaturated fatty acids and disaccharides.

BN %

40

30

250” I-----iSOTHEf?MAL_75YMIN

20 MINUTES

IO

250” 2.20’ 190” 160” TEMPERATURE K.) PROGRAM

q 15C”

---+--075”/MIN--i RATES

c

-750 YRS. SEDIMENT HYDROLYSATE. TRIMETHYLSILYL .DERIVA;;VES.

16

Fig. 3. Gas chromatogram of sugars from the ~760 yr sediment. Peak numbers and identities are the same as in Fig. 2.

MINUTES m ~lS0THERMAL-7.5’/MIN.

25” 240’ 190. 160’ TEMPERATURE CC) .PROGRAM

-075wdIN.~ RATES

l5cP

Carbohydrates from Santa Barbara baain sediments

831

taken from blank (no injection) column runs showed only minor peaks even at maximum mu~tip~er voltage and column temperature. Since TMS sugars fragment extensively (DEJONBR:et d., 1969) and most sugars give very intense peaks at m/e 73 and m/e 204, more than one run, at different multiplier voltages, was necessary to get these peaks on scale and still not lose less intense, but important peaks, in the higher mass ranges. In order to minimize any potential errors in counting the fast scan speed spectra ( N 3 set to m/e 450) (MODZELEEXI et al., 1968) taken from the gas chromatographic runs, spectra of standard sugars

191

J

TMS RHAMNOSE, MW452

147

393

m/e Fig. 4. Spectrum A-6 is TMS rhamnose from peak 6, Fig. 1; and B-6 is TMS rhamnose from peak 6, Fig. 2.

(TMS 6 - D glucose, TMS D-xylose and TMS L-fucose) were taken a;t sfow scan speed through the solid inlet system of the mass spectrometer. TMS sugars have sufficient volatility at a vacuum of lo-+? mm Hg to exclude the need for heating the inlet system. This procedure enabled a more accurate counting of the spectra, and provided good reference spectra for three classes of sugars (i.e. hexoses, pentoses and 6-deoxyhexoses in the pyranose form). The mass spectra obtained showed good correlation with the standard mass spectra (Pigs. 4, 5 and 6). An exhaustive study has been made of the mass spectra of TMS ethers of pyranose and furanose sugars (DEJONUH et al., 1969) and the TMS derivatives of 6-deoxyhexoses have been shown to follow the same type of fragmentation pattern (CEKIZHOV et al., 1967). In general, these silylated compounds show mass losses of 15 (CH,), 89 (OTMSi), 90 (HOTMSi~ and various combinations of these. Hexose derivatives of the pyranose form give a, b, c and d as intense fragment ions, whereas in the spectra of hexoses in the furanose form the intensity of c is greatly diminished, and that of d is markedly increased. Fragment e also becomes more intense relative to c

J,

832

70 Fig.

E.

MODZELEBEI,

LAURIE

and

B.

NAOY

m/e

A-8

is TMS

xylose from

A-13

90.

A.

II0 I30 150 170 190 210 230 250 270 290 310 330 350 370 390 410 4:0

90

5. Spectrum

IOO-

W.

from peak

peak 8, Fig.

8, Fig.

1;

and C-8 is TMS

4h xylose

3.

204

8070- 73

191

H

x10 f---

TMS

OTMS

P-D-GLUCOSE,

MW

540

435

70

90

110

Ix,

150

170

190

210

230

250

270

290

310

330

350

370

390

410

430

450

470

490

510

13, Fig.

1;

and B-10

530

550

m/e Fig.

6.

Spectrum

A-13

is TMS

/?-D glucose

mannose

and ion m/e 319 shows a tenfold

from

from peak

peak

10, Fig.

increase in the fur&nose systems.

b. TMSiOCH=&TMSi

a. (CH,),& m/e 73

m/e

191

C.

;H-CH I

TMSiO

I

OTMSi

m/e 204 d. CH=CH

6H 1

I

TMSiO

OTMSi m/e 217

is TMS

2.

e. bH-OTMSi I

CH,OTMSi m/e 205

Carbohydrates

from Santa Barbara basin sediments

833

The TMS sugars were identified by their mass spectral fragmentation pattern and by their retention time on the gas chromatograph. Peaks 9, 14 and 16 (Figs. 2 and 3) on the gas chromatographic traces remained to be identified. The mass spectrum of peak 9 (Figs. 2 and 3) well fitted a pyranose hexose although the gas chromatographic standards available did not permit further identification (Fig. 7, spectrum C-9).

m/e Fig. 7. Spectrum B-14 is TMS mannitol from peak 14, Fig. 2. Spectrum C-9 is an unknown TMS pyranose hexose from peak 9, Fig. 3.

The mass spectrum of peak 14 (Figs. 2 and 3) was found to fit the published spectrum of mannitol (KXRKK;~INEN and VIHKO, 1969) (Fig. 7, spectrum B-14), although the intensity of all peaks relative to m/e 73 are somewhat lower. The difference could be caused by the fact that peak 14 (Figs. 2 and 3) may have more than one component. A co-injected standard TMS mannitol sample showed the same retention time as peak 9 (Figs. 2 and 3) and also gave the s&me mass spectrum, except that the peak intensities relative to m/e 73 were higher. In addition to normal sugar peaks, there is a very marked increase in the intensity of m/e 205 which, on the basis of the previously described structure of ion fragment e, would obviously be a much more favored fragment ion of the open chain form of the TMS sugar alcohol. The other fragmentation patterns not found in the sugsrs are shown in the fragmentation scheme overleaf. The transitions from 409+ --f 319+ and 307+ + 217+ are supported by the indicated metastable ions (m*). The mass spectrum of peak 16 (Figs. 2 and 3) is given in Fig. 8, spectrum C-16, and the intense hydrocarbon ions (m/e 41, 43, 65, 57, etc.) make it obvious that a long aliphatic chain is present. The intense M+ and M-15+ ions along with an M-59 ion, i.e. loss of CH, + CO,, indicate a long chain fatty acid TMS ester (PIERCE, 1968). The TMS ester of stearic acid was synthesized and its spectrum showed good correlation with the unknown (Fig. 8). Suggested structures for the major ion fragments are given below. Metastable ions at m/e 114.8 obs. (talc. 114.7) and m/e 103.8 obs. (talc. 103.6) support the transitions m/e 145+-+ 129+ and 132+ -+ 117+. 6

J.

834

E.

MODZELESKI,

W.

A.

~&grne~t~tion

LAURIE

and

B.

NAUY

scheme

lCHzOTMSi I TMSiO-*C---H 1 TMSiO-YL-H I H-42-OTMSi I H---43---OTMSi i %H20TMSi /

J

M+ (M.W. 614)

j (Cp-C, bond cleavage)

(C,--Cp bond cleavage)

CH~OTMSi I CHOTMSi

I

+CHOTMSi m/e 307

kHOTMSi I CHOTMSi

I

+CHOTMS~ m/e 409

m* oba. 153~3(talc. lh3-4)

Y

CH-OTMSi

II

CH I I_CHOTMSi m/e 217

1 m* oba. 249.0 (talc. 248*813

c CH-OTMSi

II

CH I CHOTMSi

I

+CHOTMSi m/e 319

Carbohydrates

835

from Santa Barbara basin sediments

TMS Stearic Acid-Major

Fragment Ions

(CII,), SiO(!X&&H~ z+

(CII,), Si-0

m/e 145

\ ! _tCK--CZ(

/

c===o

m/e 129 OH t

i (CH,), SW-C=CH, m/e 132

?I 1 -+

OH t

(CH,), &O-C=CH, m/e 117

Although stearic acid has been cited as a constituent of marine algae (CHUECOS and RILEP, 1966), palm& acid has always been regarded as being present in higher concentration. A search of the mass spectra of other gas chromato~ra~hie peaks, e.g. peak 15 (Figs. 2 and 3) showed relatively intense ions at m/e 328 and 313 for the M+ and M-15” ions of TMS palmitic acid, thus indicating the presence of this compound together with B-D glucose. Gas chromatographi~ peaks 17-20 (Figs. 2 and 3) were weak and only tentative loo 9a

80 w 7Q 0 60 2 w Qa 40

JMS STEARC ACID, M.W 356 cH3 (~~~1~6 COOTMS

5:

C-16

(M-15)

m/e Fig. 8. Spectrum C-16 is TMS steario acid from peek 16, Fig. 3. The spectrum above C-16 is a standard TMS steariio acid.

identification could be made since some peaks appeared to have more than one component. It does appear, however, that unsaturated fatty acids and disaccharides may be present in small quantities. DISCUSSION The presence of mannitol in the sediment hydrolysates, as well as a relatively large amount of fucose, suggests an algal source for these two sugars (PERCIVAL and MCDOWELL,1967; SWAIX, 1969, 1970). ~~an~tol is known to occur in the brown algae, especially the ~a~~~a~~~ce~e, in amounts up to 25 per cent of the dry weight of the whole plant, and, is also present as an end group in the polysaccharide, lamin~in (PERCIVALand MCDOWELL,1967). The other sugars found Gould be of algal origin, but it is not possible to estabIish the origin of these sugars with oertainty at this time. The presence of glucose is suggestive of a polysa~~haride of the cellulose type as additional hydrolyses of the sediment samples yielded only glucose in small amounts. The hydrolysis techniques used in this study are known to give an incomplete hydrolysis of cellulose (VOLCANI,1970). The possibility that hydrolysis of these sediments has released monosaccharides whioh were either adsorbed on the sediment surfaces or bound by a partially ionic bond to the clay minerals present in the sediments must be considered. However, in past studies with various hydrolysis techniques it was found that monosaccharides would be released under considerably less strenuous acid hydrolysis conditions than were employed in this work. In addition, the hydrolysis of samples containing monosaccharides with the amount and concentration of the acid used, usually resulted in the presence of trioses and t&roses as breakdown products of the hexoses and pentoses. There were no significant amounts of these breakdown products found in either the thin-layer or gas chromatographic analyses of the sediment hydrolysates; consequently, these observations suggest a polysacoharide origin for most of the sugars which were detected. Work currently in progress is designed to isolate the intact polysac~harides, if present, and identify at feast some of them. Since work has previously been done on the isolation of pol~sac~harides from geological sources it is not unreasonable to assume that these compounds may show a relative stability under geological eil~ironments (SwAIN, 1969, 1970). There is 50 per cent less total sugars in the N 7&O-yr sediment then in the w 50 yr sediment. The sugar Ioss seems to be largely nonselective and, as such, is not likely to be attributable to a loss through microbial metabolism. Such a loss would most likely occur as a preferential loss of one or more sugar types over the others, rather than the nonselective loss which was observed. The total organic content for the two sediments is fairly close and does not indicate that the lesser amount of sugars in the - 750 yr sample may be the result of less initial organic matter. The fact that no appreciable difference in sugar composition was obse~ed between the hy~olysates of the two sediments is indicative of a similar environment

Carbohydrates

from Santa Barbara

basin sediments

837

existing at the times of the deposition of the two sediments. The presence of at least two sugars which may be of algal origin is illustrative of the role that carbohydrate studies can play in geochemistry by determining the possible type of living matter existing at the time of a sediment formation. The presence of mannitol is especially revealing since it is commonly associated only with the brown algae (SWAIN, 1970). The nonselective loss of sugars with time suggests a mechanism of sugar depletion in these particular sediment samples that is not due to ordinary microbial metabolism. Acknowledgme&s-Tha

authors wish to thank A. SOUTAR of Scripps Institution of Oceanography, University of California at San Diego, for collecting and dating the sediment samples. The authors also wish to thank VINCENT E. MODZELESKI and WARD M. SCOTT of The University of Arizona for their technical assistance with the gas chromatograph and mass spectrometer, and B. E. VOLCANI of Scripps Institution of Oceanography, University of California at San Diego, for his personal communications regarding hydrolysis techniques. This investigation was supported by NASA grant, NGR 03-002-171. REFERENCES BLOCK R. J., DURRUNA E. L. and Zwma G. (1958) Carbohydrates. In A Manual of Paper Chromatography and Paper Electrophoresis, pp. 171-172, 192. Academic Press. CHIZHOV 0. S., MOLOSTSOV N. V. and KOC~ETKOV N. K. (1967) Mass spectrometry of trimethylsilyl ethers of carbohydrates. Carbohyd. Res. 4, 273-276. CHUECAS L. and RILEY J. P. (1966) The component fatty acids of some sea-weed fats. J. Mar. Biol. Assoc. U.K. 46, 153-159. DEJONGH D. C., RADFORD J. D., HRIB~R J. D., HANESSIAN S., BIEBER M., DAWSON G. and SWEELEY C. C. (1969) Analysis of trimethylsilyl derivatives of carbohydrates by gas chromatography and mass spectrometry. J. Amer. Chem. Sot. 91,1728-1740. DUBOIS M., GILLES K. A., HAMILTON J. K., REBERS P. A. and SMITH F. (1956) Calorimetric method for determination of sugars and related substances. Anal. Chem. 28, 350-356. ERDMAN J. G. (1964) Geochemistry of the high molecular weight non-hydrocarbon fraction of petroleum. In Advances in Organic Beochemi&y (editors U. Colombo and G. D. Hobson), pp. 215-237. Pergamon Press. KXRKK~~INEN J. E., HAAHTI E. 0. and LEHTONEN A. A. (1966) Thin layer and column chromatography of carbohydrates as trimethylsilyl ethers with applications to mucopolysaccharide analysis. Anal. Chem. 38, 13161319. KXRKKHINIXN J. and VIHKO R. (1969) Characterization of 2-amino-2-deoxy-n-glucose, 2-amino2-deoxy-n-galactose and related compounds as their trimethylsilyl derivatives by gas-liquid chromatography-mass spectrometry. Carbohyd. Res. 10,113-120. K~OEPELIN H. (1964) De6nierte chemische Verbindungen in Posidienschiefer. In Advances in Organic Geochemistry, (editors U. Colombo and G. D. Hobson), pp. 165-167. Pergamon Press. MODZELESEI V. E., MACLEOD W. D. and NAGY B. (1968) A combined gas chromatographic-mass spectrometric method for identifying n- and branched-chain alkanes in sedimentary rocks.

Anal. Chem. 40, 987-989. NAGY B., MODZELESKI V. and MTTRPHY M. T. J. (1965) Hydrocarbons

in the banana leaf, Muss

Sapientum. Phytochem. 4, 945-950. PALACAS J. G., SMITH F. and SWAIN F. M. (1959) Occurrence of carbohydrates in bituminous sedimentary rocks. Bull. Geol. Sot. Amer. ‘70, 1654. PALACAS J. G., SMITH F. and SWAIN F. M. (1960) Presence of carbohydrates and other organic compounds in ancient sedimentary rocks. Nature 185,234. PERUIVAL E. and MaDow~n~ R. H. (1967) Polysaccharides in living marine algae, Food storage polysaccharides of the Phaeophyceae and Chrysophyceae, Cellulose, and some comparisons of algal with other polysaccharides. In Chemistry and Enzymology of Marirae Algal Polysacchurides, pp. l-10, 53, 84-96, 190-194. Academic Press.

838

J. E. MODZELESKI, W.

A. LAURIE and B. NAVY

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