Preparation of calibration curves
is often more an exercise in curve preparation than a useful evaluation of patient sample accuracy and imprecision, which is best evaluated by QC samples prepared identically to patient samples.
The linearity of the method was assessed by plotting calibration curves
in plasma at seven concentration levels in triplicate on three consecutive days.
The linearity of calibration curve
was assessed by linear regression.
The regression parameters for the calibration curves
are presented in Table 2 and the corresponding curves are visualized in Figure 5.
Teachers may find hourly exposures from 9:00 am to 3:00 pm suitable for calibrating dosimeter strips during summer months when the UV exposure will be high but may prefer to calibrate over several days during winter months in order to obtain the degree of colour fading necessary to produce an accurate calibration curve
. Periods of frequent cloud will reduce the accuracy of exposure measurements over exposure intervals, as these are made by determining the average of the starting and ending exposure interval irradiance, which will be dependent on cloud cover.
To test the reproducibility of the calibration curve
, the probes were recalibrated at the same external temperature (18[degrees]C) after being used in the flow experiment for a period of 286 days.
Figure 8 gives an example of how to derive a calibration curve
and to make a MESF assignment to CD45-stained lymphocytes.
Development of Calibration Curve
One problem with this method is the difficulty of reading the result from the log/log graph paper that is required to plot the calibration curve
Calculations were made against a 5-point calibration curve
from serial dilutions of the standard stock solution.
From the calibration curve
, the amounts of arbutin and hydroquinone in different herbal slimming products were calculated.