地球化学基准与环境监测实验室分析指标对比与建议.

BACKGROUND: Global harmonious high-quality geochemical data and accompanying maps are reference baselines for quantifing future human-induced or natural environmental changes. OBJECTIVES: In order to ensure the accuracy of geochemical reference values and analytical data, advisions were made for laboratory analysis. METHODS: The analytical data of Cd, Hg and W from China, USA, Europe and Australia were compared and two analysis data of the sam laboratory in China at an interval of 15 years were also compared. RESULTS: The analysis data of cadmium in different laboratories and the same laboratory at 15-year intervals are consistent with a correlation coefficient of 0.96. But mercury is poorly consistent with a correlation coefficient of 0.74, and tungsten is not comparable with a correlation coefficient of 0.56). The analysis results of cadmium are highly consistent because the analysis method is the same and the detection limit is close. The consistency of mercury is poor, especially the low-content mercury is significantly different because the analysis method and detection limit are different. Tungsten is not comparable in different laboratories because of different laboratory analytical methods.The prerequist for recognition of environmental changes (RCenv> REsmpl+RDlab) is that the change value must be larger than the value of field sampling error (REsmpl) and laboratory analysis error (RDlab). Therefore, sampling errors and laboratory analysis errors must be minimized. CONCLUSIONS: Six general guidelines are proposed. 1) The original sample was separated through a 10-mesh sieve and processed to a particle size of less than 200 mesh using pollution-free method. 2) A total of 71 elements plus other parameters should be determined by well-established mulitiple analyticalmethods, e.g., fussed glass bead-XRF for major elements and 4-acids ICP-MS and ICP-OES for minor elements in combination with other methods. 3) The method detection limits must be lower than crustal abundance of the chemical elements and reportable data percentage must be more than 90%. 4) The geochemical reference materials used for quality control should contain the reported certified CRM values for all elements. 5) Analytical relative errors for the triplicate samples should be less than 40% (RD ≤ 40%) if concentration of the element is less than 3 times detection limits, and less than 20% (RD ≤ 20%) for the elements with concentration more than 3 times detection limits as well as major elements, Fe-group elements and toxic metals. 6) The total contents of major elements SiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, Na2O, K2O, TiO2, P2O5, H2O+, CO2, SO2 and organic maters or those of SiO2, Al2O3, Fe2O3, FeO, MnO, MgO, CaO, Na2O, K2O, TiO2, P2O5,and LOI should be at 99.3%-100.7%. [ABSTRACT FROM AUTHOR]