Chemical Hydrocarbon Analyses Performed at ERCO 



For hydrocarbon analyses the samples were thawed, dried with 

 methanol and extracted by high energy shaking with a mixture of 

 methylene chloride-methanol (9:1). The extract was fractionated into an 

 aliphatic (f ) fraction and an aromatic (f ) fraction using silica 

 gel/alumina column chromatography. A 1 cm diameter X 25 cm column (1 cm 

 alumina on top of 15 cm silica gel) was used. The f. fraction was 

 eluted with 18 ml hexane; the f fraction subsequently was eluted with 

 21 ml of a 1:1 mixture of hexane-methylene chloride. After reducing the 

 volume of solvent by evaporation, the gross amount (weight) of 

 hydrocarbon in each fraction was determined gravimetrically from an 

 evaporated and dried aliquot of the extract. The extracts were 

 subjected to quantitative glass capillary-gas chromatographic (GC) 

 analysis. Selected aromatic fractions also were analysed by combined 

 glass capillary gas chromatographic/mass spectrometric (GC/MS) analysis 

 for qualitative identification of individual compounds and 

 quantification of minor components. Participation in an 

 intercalibration exercise under the direction of the National Analytical 

 Laboratory indicated that these analyses were at the state^ of the art 

 with repeatable ± 20% detection of hydrocarbons in the ng g dry weight 

 sediment range. The details of GC and GC/MS analysis employed are as 

 follows: 



CC: Hewlett Packard 5840A reporting GC with glass; splitless 

 injection inlet system; 30 m glass capillary column coated with SE-30 (s 

 100,000 theoretical plates); FID detector; temperature programmed at 

 60-275°C min ; helium carrier gas 1 ml min ; transmission of 

 integrated peak areas and retention time through HP 18846A digital 

 communications interface to a PDP-10 computer for storage, retention 

 index and concentration calculations. Deuterated anthracene (f.) and 

 androstane (f ) were used as internal standards and response factors 

 were determined with known concentrations of the reported compounds. GC 

 analysis was used to quantitate components of the f. fraction. 



GC/MS: Hewlett Packard 5985 quadrapole system (GC/MS Computer); 

 mass spectrometer conditions: ionization voltage=70 eV, electron 

 multiplier voltage=2200 V, scan conditions 40 amu to 500 amu at 225 amu 

 s~ . Quantification of components of the f fraction was accomplished 

 by mass f ragraentography wherein the stored GC/MS data is scanned for 

 parent ions (m ) . The tabulated total ion currents for each parent ion 

 is compared with deuterated anthracene (internal standard) and an 

 instrumental response factor applied. Authentic polynuclear aromatic 

 hydrocarbon standards were used to determine relative response factors 

 (when no standard was available a response factor was assigned by 

 extrapolation) . 



In vitro Biodegradation 



Sediment was collected at sites 6 and 7 in November, 1979 for in 

 vitro biodegradation experiments. Replicate one hundred gram portions 

 of sediment were placed into 250 ml flasks to which 50 ml of a sterile 

 solution containing 0.5% KNO + 0.5% KH 2 P0 4 and 0.5 ml of light Arabian 

 crude oil were added. The flasks were agitated on a rotary shaker at 



