Here's a simple solution.
Dim datDate1 As Date
Dim datDate2 As Date
Dim lngSeconds As Long
datDate1 = CDate("2005/10/12")
datDate1 = datDate1 + TimeSerial(13, 6, 28)
datDate2 = CDate("2005/10/12")
datDate2 = datDate2 + TimeSerial(13, 6, 33)
lngSeconds = DateDiff("s", datDate1, datDate2)