JPH0717003Y2 - Chromatogram baseline determination device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is used for chromatograms, and for a plurality of consecutive peaks on the obtained chromatogram, a base line for obtaining peak heights or peak areas is automatically calculated. Chromatogram baseline determination device for quantitatively determining.

[Prior Art] When a plurality of consecutive peaks are insufficiently separated, that is, when they are unseparated peaks, the peak area is greatly affected by the way of taking a baseline. The method of taking a baseline preferably differs depending on the degree of peak overlap. It is cumbersome for humans to determine this baseline for each peak in many chromatograms.

Therefore, conventionally, the operator inputs the slope of the tangent line L at the start end of the skirt of the continuous peak based on the magnitude of the drift, and the method is calculated from the relationship between the tangent line L and the valley of the peak (minimum point) in the device. Was selected and the peak area was determined.

That is, as shown in FIG. 5 (A), when the operator inputs the slope of the tangent line L, the apparatus uses the vertical division method shown in FIG. 6 (A) if the valleys of the two peaks are above the tangent line L. If this valley is below the tangent line L as shown in FIG. 5 (B), the peak area is automatically determined using the valley crossing method shown in FIG. 6 (B). In the figure, BL _{1 to 3} are baselines.

This method is clear when the number of peaks with insufficient separation is two, but as shown in FIG. 7, when the number of peaks is three or more, the setting of the slope of the tangent line L becomes unknown.

In order to solve this problem, for example, when performing a drug sampling inspection using an autosampler, a chromatogram is displayed on the CRT, and a person moves the cursor to display a baseline line as shown in FIG. 3 (A). The starting point time t _s and the ending point time t _e were specified, and for the same type of drug, the starting point time t _s and the ending point time t _e were all assumed to be the same, and a baseline was drawn to obtain the peak area.

[Problems to be solved by the device] However, if the holding time is slightly changed as shown in FIG. 3 (B) due to changes in column temperature, changes in sample concentration, pulsating flow, column deterioration, etc., the baseline is inappropriate. Therefore, an accurate peak area cannot be obtained. Therefore, in order to obtain an accurate peak area, it is necessary to specify the start time and end time of the baseline each time, which is extremely complicated.

In view of the above-mentioned problems, the object of the present invention is that even if the retention time shifts due to changes in conditions, and even if there are unseparated peaks,
It is an object of the present invention to provide a chromatogram baseline determining apparatus that automatically obtains a baseline for obtaining an accurate peak area or an accurate peak height.

[Means for Solving Problems] In order to achieve this object, in the chromatogram baseline determining apparatus according to the present invention, as shown in FIG. 1, a preliminary setting means for presetting the starting point time and the ending point time of the baseline. A storage means for storing the supplied chromatogram data, a peak bottom position determining means for determining the bottom position of the peak of the stored chromatogram based on the slope or the minimum value of the chromatogram, and the preset Baseline determining means having the skirt position closest to the start point time as a start point, the skirt position closest to the preset end time as the end point, and a straight line connecting the start point and the end point as a baseline between the two points And are characterized by having.

[Embodiment] An embodiment of the present invention will be described with reference to the drawings.

FIG. 2 is a block diagram of the embodiment and shows a chromatogram baseline determining device. This chromatogram baseline determination device is applied to sampling inspections of the same type of chemicals, chemicals, biological samples, etc., and the chromatograms of each sample are substantially the same.

In the figure, 10 is a chromatogram detector, which detects chromatogram data such as absorbance.

12 is an A / D converter, which converts analog chromatogram data into digital values.

Reference numeral 14 is a display device, for example, a CRT display, which displays a chromatogram.

Reference numeral 16 denotes a keyboard, which is an index for determining an appropriate base line as shown in FIG. 3 (A) by looking at a specific chromatogram displayed on the display device 14 or using the data acquired previously. The start point time t _s and the end point time t _e are preset.

A recording device 18 records the retention time of the peak, the peak area and the peak height.

Reference numeral 20 denotes a microcomputer, and FIG. 2 shows its software configuration by functional blocks 20a to 20h.

Reference numeral 20a denotes a chromatogram storage unit, which is composed of, for example, a RAM, and sequentially writes the chromatogram data supplied from the A / D converter 12.

Reference numeral 20b denotes a peak bottom position determining unit, which determines the peak bottom positions P ₁ , P ₂ , P ₃ , P ₄ from the stored chromatogram data as shown in FIG. 3 (C). The hem positions P ₁ and P ₄ are obtained as positions where the tangent slope has a predetermined value, and the hem positions P ₂ and P ₃
Is calculated as the position of the minimum value.

20c is a baseline start point position determination unit, and a peak skirt position determination unit 2
Of the hem positions from 0b, the hem position closest to the start time t _s preset by the keyboard 16, P _{1 in} FIG. 3 (C).
Is determined as the starting point position.

20d is a baseline end point position determination unit, and a peak skirt position determination unit 2
Of the hem positions obtained in 0b, the hem position closest to the end time t _e preset by the keyboard 16, FIG. 3 (C)
Then, P ₃ is determined as the end point position.

20e is a base line decision unit, 20c, the determined start position and end position 20d, in the above example obtains a straight line connecting the P ₁ and P ₃ as base line BL between the two points.

Reference numeral 20f is a peak area calculation unit, which uses the chromatogram data stored in 20a and the baseline data obtained in 20e to obtain peak areas S ₁ and S ₂ shown by diagonal lines in FIG. 3 (C). .

Reference numeral 20g denotes a peak apex position determination unit, which uses the data between the baselines P ₁ P ₃ among the chromatogram data stored in 20a to determine the peak apex positions T ₁ , T ₂ (see FIG. 3 (C)). Ask for.

Reference numeral 20h denotes a peak height calculation unit, which calculates peak heights H ₁ and H ₂ from the peak apex positions T ₁ and T ₂ calculated from 20g and the base line BL calculated from 20e.

Next, the operation of this embodiment configured as described above will be described.

The operator looks at the chromatogram of the first sample to be sampled displayed on the display device 14 or operates the keyboard 16 by using the previously acquired data, and as shown in FIG. 3 (A). , The baseline start time t _s and the baseline end time t _e are preset.

By this, the time coordinate value of the hem position obtained in 20b and
t _s and t _e are compared, and the hem positions that are the closest to each other are set as the starting point position and the ending point position of the base line, the base line is obtained by 20e, and then the peak area is obtained and stored in the recording device 18. . When t _s and t _e are set by looking at the chromatogram, the values are the same as or extremely close to the obtained time coordinate values of the tail position.

Further, the time coordinate value of the peak apex position obtained in 20g is the retention time of the peak, the peak height is obtained by 20e from the peak apex position and the obtained baseline,
The retention time and the peak height are recorded in the recording device 18.

The same processing as the above processing is performed on the other extracted samples. However, since the start time t _s and the end time t _e are used, it is not necessary to input them each time.

(2) Expansion Note that the present invention includes various modifications other than the above.

For example, in FIG. 3C, the line connecting the hem position P ₃ which is the end point of the base line BL and the hem position P ₄ at the right end of the continuous peak is used as the base line, and the peak area and the like are obtained in the same manner. Good. The same applies when there are four or more peaks.

Further, as shown in FIG. 4, the baseline end time t _e is set as the start time of another baseline, and the end time t _e1 of this baseline is separately set so that two baselines are automatically determined according to the chromatogram. Good. The same applies to three or more baselines.

Further, in order to set the start point time and the end point time, the cursor may be moved on the chromatogram curve on the display to set the start point position and the end point position. In this case, the position coordinates also include time coordinates, and thus are included in the above claims.

[Effect of the Invention] In the chromatogram baseline determining apparatus according to the present invention, the skirt position of the peak is obtained based on the slope or the minimum value of the chromatogram, and the skirt position closest to the preset baseline start time is set as the starting point. Similarly, since the hem position closest to the preset baseline end time is set as the end point and the straight line connecting the start point and the end point is set as the base line between the two points, the column temperature change, the sample concentration change, the pulsating flow, Even if the retention time is changed due to column deterioration, etc., and even if it is an unseparated peak, it has the excellent effect that the base line is automatically corrected properly, and the accurate peak area or peak can be obtained without complicated operations. It greatly contributes to the height.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIG. 2 is a block diagram of a chromatogram baseline determining apparatus according to an embodiment of the present invention, and FIGS. 3 and 4 are for explaining how to obtain a baseline. Chromatograms and FIGS. 5 to 7 are diagrams for explaining a conventional method of obtaining a baseline. In FIG. 2, 20 is a microcomputer.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Yuzuru Sato 5 2967, Ishikawa-cho, Hachioji-shi, Tokyo 5 JASCO CORPORATION (56) References JP-A-56-22955 (JP, A) JP-A-56 -6157 (JP, A) JP 56-12550 (JP, A) Actually opened 56-92855 (JP, U) Actually opened 61-163980 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A preliminary setting means for presetting a start time and an end time of a baseline, a storage means for storing supplied chromatogram data, and a skirt position of a peak of a stored chromatogram. Or a peak skirt position determining means obtained based on a minimum value, the skirt position closest to the preset start point time as a start point, and the skirt position closest to the preset end time as an end point, and the start point A chromatogram baseline determining device, comprising: a baseline determining means having a straight line connecting the point and the end point as a baseline between the two points.