HPLC-grade acetonitrile and glacial acetic acid were also supplied by Panreac. The ultrapure water was obtained from a Milli-Q water purification system (Millipore, Bedford, MA, USA).
HPLC-grade acetonitrile and glacial acetic acid were also suppliedby Panreac. The ultrapure water was obtained from a Milli-Qwater purification system (Millipore, Bedford, MA, USA).