The main reasons which allow an interruption of the prayer are quoted in the answers of my former question Can an Imam interrupt a prayer for some reason?
- The cry of a Mazloum requesting assistance.
- When an asset valuing more than a Dirham is stolen, even if it belongs to someone else.
- In the fear of, a wolf attaching a sheep.
- In the fear of, a blind man falling into a well.
- Any other act in the spirit of aforementioned.
- Loosing the taharah while praying
It is preferable to interrupt the prayer by either performing one tasleem or any action which isn't a part of the prayer.
These are the main conditions for fard (obligatory) prayers and they are related with the purity of the person and the fear of a damage or death etc.
While in the case of optional prayers the matter is taken less strictly. For example there are ahadith showing that one should respond to the call of parents while praying a nafl prayer.
Among these reason work is certainly not an important part, so you can certainly not interrupt your fard (obligatory) prayer for a reason related to your work, but in case of nafl you might for example be allowed to respond a phone call etc.
Also note that there are two main opinions on what to do after the interruption according to a fatwa of sheikh al-Albani posted here in Arabic:
- redo the prayer (this was so far the only opinion I knew of).
- start from where you stopped, but you can only built on a full raka'a as it seems, and I'd assume (as I have no idea how this is exactly meant) that for this the interruption must be very short, for example for the time to save a soul, or perform wudu' after loosing taharah.