Purposive sampling is usually associated with qualitative methods. If you are working with quantitative methods, then it would help to hear more about the population in your study and the research questions that you want to answer.

Purposive sampling results will be biased. You have to see the nature of the population, based on which you can opt random sampling (may be stratified). Pl be very specific to the objective. 

Thaks

If the subjects under study are known and the subjects are likely to give the required information then purposive sampling is appropriate.