Yes, you can use PCR primers for sequencing, provided that they meet these stipulations: 

• The residual PCR primers must be removed from the reaction before submitting it for sequencing.
• The primers you are using must be compatible with the specific sequencing conditions. 

PCR reactions can only be quantitated successfully with a very sensitive spectrophotometer. If you don’t have one, you will need to use an analytical gel to estimate the concentration.