I have several long strings of text in which I would like to separate the
first sentance ending in ". " into another field. Which function would I need
to use. Any help would be greatly appreciated.

Example:
(1) Conformance. Cylinders shall comply with DOT specifications and shall
be.....

(1) Conformance. (cell 1)
Cylinders shall comply with DOT specifications and shall be.....(cell 2)