title: Long-term stability of pure standards and stock standard solutions for the determination of pesticide residues using gas chromatography.
abstract: 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.
authors: National Agricultural Research Foundation (N.AG.RE.F.), 1 S. Venizelou St., 141 23 Lycovrisi, Athens, Greece. lizavram@otenet.gr
authors: Elizabeth J
authors: EJ
authors: Avramides
mesh_terms: 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
chemical_list: D010573:Pesticide Residues; D010575:Pesticides