0187-5779 0187-5779 S0187-57792012000400291 Mexico Mexico 00 12 2012 00 12 2012 30 4 291 301

1993 11 121-6 1993 44 1083-7 2006 65 169-81 2006 285 187-95 2005 276 359-67 2001 85 517-47 1998 117 1487-94 1989 39 345-50 2005 373-415 2000 46 298-304 2005 43 445-8 2000 225 193-200 2003 7 39-43 Association of Official Analytical Chemists 2000 2009 115 1357-63 1993 84 407-12 1970 100 1383-8 2004 36 1553-8 2002 76 66-76 2001 41 81-5 2002 61 203-15 2008 100 254-68 2003 12 155-64 2006 57 3595-600 Secretariat of ISOSC 1984 Wageningen, The Netherlands 633-50 2000 51 401-32 2004 52 5378-82 2004 55 1927-37 2001 27 55-61 2010 153 1871-7