Each wet plankton sample was saponified (under nitrogen) 

 with 0.5 N KOH-methanol in tightly capped centrifuge tubes stan- 

 ding in a boiling water bath for 30 min. The resulting mixtures were 

 cooled and the hydrocarbons (with nonsaponifiable lipids) were ex- 

 tracted three times with 10 ml portions of hexane. The hexane ex- 

 tracts were evaporated to 0.5 ml on a rotary evaporator at 30 °C. 

 One n 1 of this extract was injected into a Hewlett Packard 5840A 

 gas chromatograph equipped with a 15 m OV-101 glass capillary 

 column. The injection and programming conditions are given in 

 Table 2-4. 



Three types of standards were used in this study. For quantifi- 

 cation, a measured amount of a mixed gasoline standard (1:1:1:1:1, 

 Tank 1 Starboard, Tank 1 Port, Tank 2 Port, Tank 3 Port, and 

 Tank 4 Port) was carried through the entire saponification- 

 extraction procedure. The hydrocarbon activity of this process stan- 

 dard was limited to peaks between retention times (RT) of and 25 

 min, boiling range about ~C 6 -C U (see Fig. 2-6). The areas under 

 each peak in the plankton sample chromatogram from RT = 7 to 

 25 min were summed. The area was related to concentration by use 

 of a calibration curve constructed using various injection volumes 

 of the processed standard. It was necessary to construct a calibra- 

 tion curve using this gasoline standard because the relationship be- 

 tween area and concentration was not linear and did not intercept 

 zero. The two other standards, a nonprocessed gasoline mixture and 

 a water-accommodated gasoline standard were used for matching 



Table 2-4.— Glass capillary analytical conditions, Ocean 250 spill. 



Volume injected 

 Column 

 Column flow 

 Auxiliary flow 

 Programming 



Instrumentation 



1 v> 1 



glass capillary, OV-101, 15 m, 0.25 mm i.d. 



1.7 ml/min 



21.5 ml/min 



Temperature 1 = 35 °C, held for 5 min, 

 then the temperature was increased at a 

 rate of 4 °/min up to 250 °C 



Hewlett Packard 5840A gas chromato- 

 graph with integrator 



purposes employing the procedure of Hoffman and Quinn (1978). 



Results and discussion. — The quantitative results for the 

 plankton samples are given in Table 2-5. While each plankton sam- 

 ple had readily measurable amounts of hydrocarbons, presumable 

 natural and anthropogenic sources, only one sample (205) had 

 hydrocarbon activity in the boiling range (Q-CO of the gasoline 

 components. A comparison of the plankton sample, having 

 gasoline components with one example of plankton with little or 

 none of these components, is illustrated by chromatograms in 

 Figure 2-7. The values given in Table 2-5 do not reflect total 

 hydrocarbons. Total hydrocarbons for open ocean plankton 

 samples have been previously shown to be on the order of 1-6"% of 

 the total lipid material (Lee et al. 1971). On a dry weight basis, this 

 would represent 2,000 /ug/g- Total hydrocarbons in Georges Bank 

 population have been reported in the range between 54 g/g and 

 1 1 ,000 g/g (Boehm 1977'). The detection limits are also given in 

 Table 2-5. Due to the high concentration of total hydrocarbons in 

 each sample, it was not feasible to inject larger amounts into the 

 chromatograph in order to attempt to see lower concentration levels 

 of gasoline components without overloading the column severely 

 with the higher molecular weight fraction. One persistent problem 

 which affects all plankton analyses results from passing large 

 volumes of water through a net to collect the plankton. Adsorption 

 of organic material to the net and to particle surfaces during collec- 

 tion may also result in the collection of hydrocarbons from the 

 water as well as hydrocarbons associated with the plankton. Since 

 previous studies have reported net fouling after oil spills (Gross and 

 Mattson 1977), it is uncertain whether the high value found in 

 plankton sample 205 was associated with the plankton or was col- 

 lected from the water column. 



'Boehm, P. D. 1977. Hydrocarbon chemistry. In New England En- 

 vironmental Benchmark, Fourth Quarterly Summary Report, October 13, 1977, 

 Energy Resources Co. (BLM Contract AA 550-CT6-51), Chapter 5.1. Energy 

 Resources Co., 185 Alewife Parkway, Cambridge, MA 02138. 



INCREASING TIME AND TEMPERATURE 



Figure 2-6.— Chromatognun of gasoline mixture from the Ocean 250 spill carried through saponification-ertraction procedure. 



10 



