title: Inter-laboratory exercise on antibiotic drugs analysis in aqueous samples.
abstract: An inter-laboratory exercise was organized under the PHARMAS EU project, by the Advanced School of Public Health (EHESP), in order to evaluate the performances of analytical methods for the measurement of antibiotics in waters (surface and tap). This is the first time such an exercise on antibiotics has been organized in Europe, using different kinds of analytical methods and devices. In this exercise thirteen laboratories from five countries (Canada, France, Italy, the Netherlands and Portugal) participated, and a total number of 78 samples were distributed. During the exercise, 2 testing samples (3 bottles of each) prepared from tap water and river water, respectively, spiked with antibiotics, were sent to participants and analyzed over a period of one month. A final number of 77 (98.7%) testing samples were considered. Depending on substances studied by each participant, 305 values in duplicate were collected, with the results for each sample being expressed as the target concentration. A statistical study was initiated using 611 results. The mean value, standard deviation, coefficient of variation, standard uncertainty of the mean, median, the minimum and maximum values of each series as well as the 95% confidence interval were obtained from each participant laboratory. In this exercise, 36 results (6% of accounted values) were outliers according to the distribution over the median (box plot). The outlier results were excluded. In order to establish the stability of testing samples in the course of the exercise, differences between variances obtained for every type of sample at different intervals were evaluated. The results showed no representative variations and it can be considered that all samples were stable during the exercise. The goals of this inter-laboratory study were to assess results variability when analysis is conducted by different laboratories, to evaluate the influence of different matrix samples, and to determine the rate at which participating laboratories successfully completed the tests initiated.
authors.affiliation: Environment and Health Research laboratory (LERES), Advanced School of Public Health (EHESP), Avenue du Professeur Léon Bernard-CS 74312, 35043 Rennes Cedex, France. benoit.roig@ehesp.fr
authors.forename: B
authors.initials: B
authors.lastname: Roig
authors.forename: M
authors.initials: M
authors.lastname: Brogat
authors.forename: S
authors.initials: S
authors.lastname: Mompelat
authors.forename: J
authors.initials: J
authors.lastname: Leveque
authors.forename: A
authors.initials: A
authors.lastname: Cadiere
authors.forename: O
authors.initials: O
authors.lastname: Thomas
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000592:standards; D002170:Canada; D060766:Drinking Water / Q000737:chemistry*; D004784:Environmental Monitoring; D005602:France; D005618:Fresh Water / Q000737:chemistry*; D006801:Humans; D007558:Italy; D007753:Laboratories / Q000592:standards / Q000706:statistics & numerical data; D009426:Netherlands; D015588:Observer Variation; D011174:Portugal; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000592:standards
chemical_list: D000900:Anti-Bacterial Agents; D060766:Drinking Water; D014874:Water Pollutants, Chemical