0121-4004 0121-4004 S0121-40042006000200002 Colombia Colombia 00 00 2006 00 00 2006 13 2 13 19

1 1987 7 189-91 2 2000 267 3 2004 81 6 6 752-758 4 2000 5 1991 2 440 6 7 1976 72 248-254 8 Association of Official Analytical Chemist 1890 9 2000 26 53 53 21-34 10 1993 1 451 11 2003 4 3 3 139-46 12 2003 173 13 1994 4 759