CPC G01N 33/1826 (2013.01) [G01N 1/10 (2013.01); G01N 1/405 (2013.01)] | 14 Claims |
1. A sampling device comprising:
a liquid inlet;
a first layer downstream of the liquid inlet, the first layer comprising a first solid phase extraction medium, the first layer further comprising a first derivatizing agent for a first targeted analyte, reaction between the first derivatizing agent and the first targeted analyte forming a first derivatized analyte;
a second layer downstream of the first layer, the second layer comprising a second solid phase extraction medium, the second layer further comprising an isotopically labeled analogue of the first derivatized analyte; and
a liquid outlet downstream of the second layer.
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