title: Interlaboratory study to improve the quality of trace element determinations in rainwater.
abstract: This is the first publication which describes the development of a reference material (RM) for the determination of 11 trace elements (Cu, Pb, Mn, Ni, Zn, Fe, Cd, Co, V, As and Al) in rainwater at microgram per liter concentrations. An interlaboratory comparison study for the determination of trace elements in rainwater was carried out for material performance studies to establish analyte concentrations with a stated uncertainty. Fifteen reputed laboratories from Asia, Europe and North America participated in the study. These laboratories used their regular in-house methods to analyze the rainwater samples. The aim of this study is to establish concentration levels of trace elements in rainwater based on interlaboratory study results. Details of the production, homogeneity and stability of the reference sample are given in this article. The organization of the study and the quality assurance measures undertaken at the organizer's laboratory are described. The analytical results obtained from individual laboratories and the analytical methods used for the determination of trace elements in rainwater are discussed. Based on the results obtained from the intercomparison study, certified values as well as informative values are assigned to the 11 trace elements in rainwater.
authors.affiliation: Division of Environmental Science and Engineering, National University of Singapore, Block EA, 2 Engineering Drive 1, Singapore 117576, Singapore.
authors.forename: Sathrugnan
authors.initials: S
authors.lastname: Karthikeyan
authors.forename: Rajasekhar
authors.initials: R
authors.lastname: Balasubramanian