The International Mussel Watch 



m. HPLC with normal phase silica column (high-resolution silica, Petrick, etal., 1988). 



n. Gas chromatograph with electron capture detector and appropriate silica capillary column 

 (see 5.3). 



o. Vacuum pump (water-jet air pump). 



4. Preparative Analytical Procedures 



4. 1 Cleaning of glassware 



Scrub all glassware vigorously with brushes in hot water and detergent. Rinse five times 

 with tap water and twice with distilled water. Bake overnight in an oven at 300°C. All glassware 

 should be stored in dust-free cabinets and tightly sealed with precleaned aluminium foil when not 

 in use. Ideally, glassware should be cleaned just before use. If necessary, to remove tough 

 organic residues, the glassware must be soaked for at least two hours in the nitrosulphuric acid 

 cleaning solution, thoroughly rinsed with tap and distilled water and then put into the drying oven. 



4.2 Extraction procedure 



Select approximately 1/4 of the sample which has been previously ground in Na2SO"4 and 

 subsample into three aliquots. Aim to end up with approximately 75 mg lipid. Transfer the 

 mixture to a precleaned glass extraction thimble, add internal standards and extract with about 200 

 ml hexane/pentane or hexane:acetone (90:10) in N2-atmosphere for 8 hours in the Soxhlet 

 apparatus cycling 4 to 5 times per hour. Extract the same amount of sodium sulfate for a 

 procedural blank. 



Alternatively, the Na2SO"4 -sample may be extracted with solvents in a Tissumizer using 

 CH2CI2 and 8 or 9:1 Na2S04to wet tissue ratio. The procedure is described in detail in MacLeod 

 etal., 1985. 



Sample Extraction (adapted from: MacLeod etal., 1985) 



1 . Using a spatula, and being careful to place the sample on the bottom and not the sides, 

 weigh 3 + 0.5 g of sample to the nearest 0.01 g into the 50 ml screw cap centrifuge 

 tube. (Set aside ca. 1 g for Dry Weight Determination) 



88 



