Absorbance analyzer and data processing method for chromatograph

DETAILED DESCRIPTION An object of the present invention is to provide an absorbance analyzer for obtaining time change of a specific functional group which is contained in a sample by removing influences by other functional groups and fluctuation of a base line.
FIG.
1 illustrates a mode of the present invention.
A measuring part 2 is adapted to measure the absorbance spectrum of an effluent fluid sample from a chromatograph in a constant cycle, and a base line calculating part 4 decides a base line including absorbance values on both ends of a designated wave number range with respect to measurement data of every absorbance spectrum measured by the measuring part 2, while a peak area calculating part 6 calculates the peak area of the absorbance spectrum in the designated wave number range on the basis of the decided base line.
A chromatogram is obtained by time change of the peak area which is calculated by the peak area calculating part 6.
FIG.
2 shows an exemplary operation of the present invention shown in FIG.
1.
Referring to FIG.
2, an area I(t) obtained by subtracting a region I.
sub.
2 (t), which is enclosed by a trapezoid formed by connecting absorbance values of .
nu.
.
sub.
1 and .
nu.
.
sub.
2 by segments, from an integral value I.
sub.
1 (t) of an absorbance spectrum A(t, .
nu.
) in the designated wave number range .
nu.
.
sub.
1 to .
nu.
.
sub.
2 indicates the absorbance of the target region.
This is expressed as follows: ##EQU2## where .
nu.
represents the wave number in the absorbance measurement, and A(t, .
nu.
) represents the absorbance spectrum of the sample changing over time, with the integration range of .
nu.
.
sub.
1 to .
nu.
.
sub.
2 (.
nu.
.
sub.
1 <.
nu.
.
sub.
2).
The integral value I.
sub.
1 (t) obtained in the designated wave number range .
nu.
.
sub.
1 to .
nu.
.
sub.
2 includes a fluctuation component of the base line in this wave number range, due to the absorbance spectrum of an adjacent functional group, a fluctuation factor appearing on the spectrum, and the like.
A stable chromatogram can be obtained by subtracting the area I