6 compares the SR-FTIR and
titrimetric PV results obtained for this series. As can be seen,
the results from the two methods parallel each other at the upper
end of the range, but the titration method starts to fail at PV
values below 1.0 meq/kg, while the SR-FTIR method responds
linearly down to∼0.50 meq/kg, with an S.D. of±0.018 meq/kg.