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Function and setup multi N/C pharma UV
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The calculated parameters appear in the method in the TIC analysis channel. The
calculation of the analysis results is based on the calculated calibration function.
Generally separate calibration functions are calculated for the channels TC and TIC in
accordance with the equations (4) or (5). The equations (6) and (7) apply.
The calculation of the analysis results is based on the calculated calibration functions
for TC and TIC. The TOC content is then the result of the equation (8).
𝑐𝑐
𝑇𝑇𝑇𝑇𝑇𝑇
= 𝑐𝑐
𝑇𝑇𝑇𝑇
− 𝑐𝑐
𝑇𝑇𝑇𝑇𝑇𝑇
(8)
The calculated parameters appear in the method in the TIC and TC analysis channels.
The calibration takes place parallel by default, usually with mixed standards (e.g.
carbonate/hydrocarbonate and potassium hydrogen phthalate or saccharose).
The calibration of the TIC and TC channel can also be carried out consecutively with
separate standards. This is often useful if different ranges are to be calibrated for TC
and TIC.
The method NPOC plus is calibrated the same way as the method TOC(Diff). Since the
TIC is largely purged when using the NPOC plus method, it is important to calibrate a
low operating range for the TIC calibration.

separate calibration of TIC and TC channel

measurement of samples and calculation of the analysis results

Purging the acidified sample (3 to 5 min)

detection of the remaining TIC content – concentration is calculated in
accordance with the calibration curve

detection of the remaining TC content – concentration is calculated in
accordance with the calibration curve

calculation of the TOC content in accordance with the equation (8) from the
calculated concentration difference
It is useful to carry out a matrix-dependent calibration. For this the carbonate standard
is added in the range of the sample concentration to be expected. This comes closest
to the NPOC plus principle.
3.4.4 Method characteristics
The remaining standard deviation (remaining variance) expresses the dispersion of
the integers around the regression function (regression precision).
The standard deviation of the method describes in a unique and general way the
quality of the calibration. For the unique evaluation of the quality the standard
deviation of the method must be used.
The variation coefficient of the method (relative standard deviation of the method)
should be used for the comparison of different calibrations with different calibration
ranges.
TOC (Diff)
NPOC plus
Remaining standard
deviation
Standard deviation of the
method
Method variation
coefficient