Addressing Carryover During Sample Analysis

A general discussion of carryover and of methods to address it can be found in Section 9.7.2 and some implications for validation are described in Section 10.2.9b. Here an approach is described that facihtates formulation of a 

The basis of this approach was the experimental demonstration of the constancy over a wide range of concentration of the relative carryover (RC) defined as  

Several different experiments were conducted (Zeng 2006) to confirm the constancy of RC to within a few percent these are not summarized here but this result should be re-confirmed for any different method (of course the value of RC need not be the same as the value of 0.05 % = 5 X 10 found for the method in the original work). Based on this result, the approach can be based on evaluation of the estimated carryover influence (ECl) on a chromatographic peak area as  

In general the total uncertainty in a measured value can be considered to be the sum of the systematic error(s) plus the random error (often expressed as the relative standard deviation, RSD). The systematic error can be estimated as the ECI plus any other systematic errors in the system. 

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