Table 1-2. Relative Standard Deviations 



In contrast are the group B metals which consist of Al, Ca, Co, and Ti. As 

 shown in Table 1-2, these metals are characterized by a much higher relative 

 standard deviation, from 14% to 38%. When plotted in a fashion similar to 

 Figure 1-1, they show a much higher degree of scatter. Accordingly, the 

 correlation coefficients show no real correlations at the 95% confidence level. 



Although this material has been prepared as a reference material, it is in no 

 way equivalent to a standard reference material such as those developed by the 

 National Bureau of Standards (NBS) (4). The NBS Standard Reference 

 Materials are certified as to their trace element content on the basis of analysis 

 by at least three independent techniques. Our material is an internal reference 

 material, not a certified standard. 



This material is now in routine use within our laboratory. One sample, 

 randomly chosen from the sequence, is included with each group of 15 

 unknown samples prepared and analyzed. Thus, there is continuous verification 

 of analytical results irrespective of operator, instrument settings, or standards. 

 In addition, this material is ideal for methods development and intercalibration 

 because of its extremely low variability. Individual organisms from a wild 



