5. Check the injection syringe for bubbles. You do not want to inject bubbles into the instrument. If you see bubbles in the syringe, empty the syringe into a waste beaker and redo Step #4. The sample ...

A 5-mL portion of each diluted sample was further diluted to 50 mL with HPLC-grade water and 20 µg of internal standard per milliliter. Before injection into the HPLC system, each standard and ...