Long-term stability of pure standards and stock standard solutions for the determination of pesticide residues using gas chromatography.
The regular replacement of pure standards used in pesticide residue analysis laboratories and frequent preparation of stock standard solutions, both required by many accreditation bodies, impose considerable demands on a laboratory's resources. In this study, pure standards for all but one (heptenophos) of 118 different pesticides amenable to analysis by GC, and stock standard solutions (1000 microg/ml) prepared from these in toluene, acetone or ethyl acetate have been shown to be stable at < or = -20 degrees C over long periods: 4-13 and 2-8 years, respectively, for pure standards and solutions. Suitable solvents, containers and handling procedures are essential to avoid evaporation from solutions.
Avramides
Elizabeth J
EJ
National Agricultural Research Foundation (N.AG.RE.F.), 1 S. Venizelou St., 141 23 Lycovrisi, Athens, Greece. lizavram@otenet.gr
D002849:Chromatography, Gas / Q000379:methods* / Q000592:standards; D004355:Drug Stability; D004356:Drug Storage / Q000592:standards; D010573:Pesticide Residues / Q000032:analysis*; D010575:Pesticides / Q000592:standards*; D012015:Reference Standards; D015203:Reproducibility of Results
D010573:Pesticide Residues; D010575:Pesticides