170135_inorganicventures_flipping

Managing Interferences

Correction equations - Polyatomic Example: need to measure 153 Eu in presence of 137 Ba

1. Concern is BaO, as 137 Ba 16 O = mass 153 2. Need to measure 137 Ba (or other Ba isotope and calculate 137 Ba) 3. Need to know BaO/Ba ratio! a. Function of instrument (tuning, introduction system) b. Function of acid matrix and concentration

c. Difficult (impossible) to determine in sample being measured * requires prior knowledge of interference production rates *

4. Calculate as with isobaric, but substitute MO + /M ratio for isotopic abundance 5. Can get messy quick: M 16 O + , M 17 O + , M 18 O + , M 16 OH + , M 35 Cl + , M 37 Cl + ….

Managing Interferences

Corrected vs. Uncorrected Results

5

Do corrections work? • Internal standards • Interference equations

Uncorrected

Corrected

4

3

2

0 to 20% difference * element specific *

1 Concentration (ppm)

0

Rb Sr Zr Nb Mo Cs Ba La Ce Pr Nd Sm Eu Gd Tb Dy Ho Er Tm Yb Lu Hf Ta Pb Th U

Element