[Question]: Parsing attribute string

[emacs]

Dear list, 

I have a quick question about parsing a string containing attributes.

My string has the following form

(setq my-string ":caption the caption :label fig-1 :width 10cm :something this is an extra option")

I'm looking for a function which produces an alist or plist with the option value pair.

(:caption "the caption"

 :label "fig-1"

 :width "10cm

 :something "this is an extra option")

As org handels these string a lot when exporting, it seems to me

that there must exist a build in function to solve this task.

Kind regards, 

Bob