Preparation of a new Certified Reference Material (CRM) for the analysis of galvanic sludge and statistical evaluation of the results of an inter-laboratory test for determination of the concentration of a part of the metallic components

Inter-laboratory tests have been organized for several years with the-aim t o compare the performance and proficiency of analytical laboratories. Parti cipation in these inter-laboratory tests can provide the possibility to fin d and quickly eliminate the errors made in the laboratory. Participation in an inter-laboratory test is usually essential for the accreditation of an analytical laboratory. The aim of our work was to organize an interlaboratory test based on the an alysis of the metals that can be determined in galvanic sludge. The galvani c sludge reference material was made from real industrial galvanic sludge b y a special preparation procedure. This sludge came from a cyanideless copp ering-nickeling-chroming and cyanideless zincing technology. The row materi al was dried and homogenized before the homogeneity tests and bottled in cl osing bottles. For the investigation of the homogeneity the results were pr ovided by an XRFS apparatus (type: ARL 8660), the statistical probe was obt ained by the help of Dixon's test, t and F probes comparing the part result s with the total of the measurement results. The elements determined from t he reference material were: Al, B, Ba, Ca, Cr, Cu, Fe, K, Mg, Na, Ni, Pb, S r, and Zn. 26 European laboratories took part in this inter-laboratory test. Following the different digestion methods, ICP-AES, AAS, XRFS, ICP-MS, spectrophotom etry, suppressor ion-chromatography, and gravimetry were used for the analy sis. The evaluation of the results of the test was made according to the re commendation elaborated by the EURACHEM and IUPAC. For the calculation of t he P- and Z-score we used the mean values and the standard deviation of the measured data of the reference laboratories that have the greatest experie nce in the field of the given analytical methods.