How to find (desi)litres from notifications

Hi,

I have loads of notifications in where has been reported added oil in (desi)litres along with some other text. Here are some examples of the data I have (Notification) and two colums I'd like to have.

Notification	Oil added	For calculation
Added DTE25 0,5l	0,5l	0,5
Added 0,5l DTE25	0,5l	0,5
5 dl of DTE25 added	5dl	0,5
0,5 litres of DTE25 added	0,5l	0,5
5 desilitres of oil added	5dl	0,5
Added 200 l oil	200l	200

Basically I'd like to search for combination of any amount of numbers (might or might not include comma) with l or dl or litres or desilitres with or without space between the numbers and the text. Is there any way this can be done?

-Anssi