170135_inorganicventures_flipping

15.13 ICP-OES Measurement

Concerns with measurement - Matrix effects - Please consider the following ques:ons before using the internal standard approach for matrix correc:on:

• Is the internal standard (IS) element compa5ble with your matrix? (Avoid using rare earths in fluoride matrices). • Are there any possible spectral interferences upon the IS line? • Is the concentra5on of the IS sufficient to give a good signal to noise ra5o? • Can your sample possibly contain the IS element as a natural component? • Is the IS clean? Are the trace impuri5es reported on the cer5ficate of analysis?

15.14 ICP-OES Measurement

Concerns with measurement - Matrix effects - Please consider the following ques:ons before using the internal standard approach for matrix correc:on:

❏ Is your method of addi1on of the IS precise? ❏ Is the same amount added precisely to all standards, blanks, and samples? ❏ Do you always use the same lot of IS for the standards and samples? (Using the same lot can be very important). ❏ If your plasma temperature were to go up or down is the IS likely to follow the same paCern of intensity change as the analyte? This is where many IS problems occur (i.e. - an IS with the same plasma / temperature behavior as the analyte is difficult [at best] to find for each analyte while avoiding other issues listed above).