1. Make sure there's no contamination

This is the effect exerted by a sample on the one that follows or precedes it (memory effect). After cleaning, a concentrated sample is analyzed three times consecutively ( H 1, H 2 and H 3, average mH ), then a low-concentration sample is also analyzed three times ( B 1, B 2 and B 3). This series of measurements is repeated three to five times. The mean values mB 1, mB 3 and mH are then calculated. The percentage of contamination is then calculated as follows:

Contamination (%) = ( mB 1 - mB 3) * 100

mH - mB 3

This memory effect should be close to zero %. This is how we test the cleaning between two analyses.