TIE cula1y:ji.s of t h e lipid extrac:t.s from samples of photosynthetic; microbial mat.(:. c;ol.lected f ran h o t spr-ings in t h r e e c x c g r a p h i c a l r e g i o n s o f ~~: e J . ~~n d diow~?d t h e p r e s e n c e of a n u r b r of C18-C21 methyl a l k a n e s , To faci 1.i t a t e t,he i d e n t . i f i c a t i c x i cif these c~cxrgcnerits a nunber of; PIS tczchnicples were explored. leadi.ng t.o t h e develoyment o f a tandem M S method which a l l w d t h e r a p i d c:haraot..er isat i o n of these c~anponemtt., Exper i m t a l :%I t. L s f ac t,o r :y ch r o m t.Wr aph ic: separ at. i CTI o f met h y 1 -br u i c h e d a1 kanes was achieved using a V a t -i a n 3400 gas chromtugr-aph w i t h a t e r q x r a t u r e pr-crgr-arrueble an-c;slumn i n ject.or E:?c&iipped with a 25111 OV-3. c a p i l l a r y colum
The column w a s i n t e r f a c e d via a h e a t e d transfer 1-ine t.o t h e i o n =mrm o f a Finnigim TSQ 70 triple quadt-upole mas s p m t r m t e r from which a l l data R r e cbt.ained. Conventional ET and C;I data were recorded scar'lning Q3 f r a n 50-500 d a l t o n s i n 1 sec. w i t h 7WV e l e c t r r m e n e r g y and 233 PA missim. Methane CI .;pectra were cht.ained by p r e s u r i s i n g t h e sxit-ce t o approximatly 0.5 Tor r