The choice of equipment depends on intended application. In case analysis of Carbon and Phosphorus is not an issue, you must seriously consider equipment working on X-Ray Flourescence. During the last five years, these equipments have gone a sea change. You no longer require Isotopes.
The advantages of X-ray flourescent equipment are many. Most striking advantages are:
-Lightweight of gun and usability under all conditions
-Does not generate an arc or a spark, which means that you could use it in an operating refinery, etc.