JP2987959B2 - Liquid chromatograph - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid chromatograph for separating and analyzing each component in a sample solution.

[0002]

2. Description of the Related Art In a liquid chromatograph, a sample solution is injected into a column by an eluent, separated into sample components by the column, eluted from the column, and detected by a detector. The retention time from the injection of the sample into the sample injection section until detection by the detector differs for each component, and the identification of the peak component is made based on the retention time of each component.

[0003]

When only the retention time under a certain elution condition is used as an identification means, if there are two or more components eluting near the same retention time, the peak component is identified. There is a high possibility of making a mistake, and the reliability of the analysis result becomes problematic. An object of the present invention is to improve the reliability of identification by using not only the retention time but also other characteristic values to identify a peak component of a chromatogram.

[0004]

As a result of examining how the retention behavior of the target peak component to be identified from the chromatogram under several kinds of elution conditions changes depending on the elution conditions, it was found that the manner of change of the retention behavior was changed. It has been found that it provides qualitative information on peak components, and this retention behavior has been added to one element of identification.

FIG. 1 shows the present invention. As an eluent, two kinds of solvents A liquid 12 and B liquid 14 are provided.
After being fed by the mixing unit 8 and mixed by the mixing unit 20, it is sent to the column 24 via the injector 22. A sample is injected into the injector 22, and the injected sample is introduced into the column 24 together with the eluent. The eluate from the column 24 is discharged via the detector 26. Liquid sending pumps 16 and 18
The flow rate is controlled by the flow rate control units 28 and 30, respectively, and the mixing ratio of the eluent sent to the column 24 is determined. The flow control units 28 and 30 control the liquid sending pumps 16 and 18 so that the mixing ratio of the eluent becomes the mixing ratio set in the concentration setting unit 32. At least two types of mixing ratios are set in the density setting section 32.

The detection signal of the detector 26 is transmitted to the injector 22
After the sample is injected, the data is input via the data input unit 34. The data input unit 34 includes an A / D converter and the like. The data captured from the data input unit 34 is stored in the data storage unit 36 as chromatogram data for each eluent having a different mixing ratio. The data storage unit 36 is prepared for the number of the mixing ratios of the eluent. For example, if two types of eluents are used,
Two types of data storage units 36a and 36b are used.

Reference numeral 38 denotes a capacity factor calculator for calculating a capacity factor k of a target component in each eluent. Numeral 40 denotes a characteristic value calculation unit, which assumes that logk = logk ₀ −SΦ (Φ is the concentration of one solvent) is established between the capacity factor k and the eluent composition Φ, and the characteristic value of the target peak component is k _0. And the slope S are calculated. Reference numeral 42 denotes a calculation result output unit that outputs the calculated characteristic values k ₀ and S.

In order to automatically obtain the identification result, a retention time setting section 44 for storing the retention time of the peak component in the eluent of each mixing ratio, a peak component in the eluent of each mixing ratio, The characteristic value setting unit 46 storing the characteristic values k ₀ and S of the target peak component, and the holding time obtained from the data storage unit 36 for the target peak component and the characteristic value k ₀ and S calculated by the characteristic value calculating unit as the holding time. It further includes an identification unit 48 for identifying the target peak component by comparing the holding time of the setting unit 44 and the characteristic values k ₀ and S of the characteristic value setting unit 46.
An output unit 50 outputs the identification result.

[0009]

In the liquid chromatograph shown in FIG.
The pump 6 and the pump 18 respectively send the solvent A solution and the solution B, and the composition Φ of the solution B with respect to the total flow rate T of both the sent solvents can be expressed as Φ = solution B flow rate / T. Where T =
The flow rate of the solution A + the flow rate of the solution B.

The chromatogram when Φ = Φ ₁ is as shown in FIG. 2A, for example, while the chromatogram when Φ = Φ ₂ is as shown in FIG. 2B. Let's say The target peak P to be identified changes as shown in the figure for each eluent composition. Where the capacity factor k is
Assuming that the retention time of the peak P is t and the column void time (time until the solvent is detected) is t ₀ , t = t
There is a relationship of ₀ (1 + k). t = t ₁ or t ₂ , k = k ₁ or k ₂ , t ₀ = t ₀₁ or t ₀₂ .

A capacity factor k is obtained for each eluent composition,
When logk is plotted against the eluent composition Φ, a linear relationship as shown in FIG. 3 is obtained. The straight line is expressed as logk = logk ₀ -SΦ. When the intercept logk ₀ and the gradient S are obtained, the characteristics of these peak components are obtained. Therefore, by comparing these characteristics with the characteristics log k ₀ , S of the standard sample, these characteristics can be used as an identification means together with the retention time. Characteristics log k ₀ may be used remains log k _0, may be used as k _0. When obtaining the relational expression as shown in FIG. 3, the eluent composition may be changed to three or more types, and the intercept logk ₀ and the gradient S may be calculated by the least square method using three or more measurement points.

[0012]

FIG. 4 shows an embodiment for carrying out the invention shown in FIG. The flow control units 28 and 30 and the concentration setting unit 3 in FIG.
2. Data input unit 34, data storage unit 36, capacitance factor calculation unit 38, characteristic value calculation unit 40, calculation result output unit 42, retention time setting unit 44, characteristic setting unit 46, identification unit 48, and identification result output unit In order to realize the CPU 50, FIG.
52, memory device 54, keyboard 56, CRT5
8. A CPU system including the printer 60 is used.

The operation of the embodiment will be described with reference to FIGS.
You. As shown in FIG. 5, the concentration of the solvent B solution is Φ₁Nana
The eluent is sent by setting the flow rates of the pumps 16 and 18 so that
Then, a sample is injected from the injector 22. Detector 26
Start data entry for the eluent concentration
Is stored in the prepared area of the memory device. Remembered
Retention time t of the target peak from the collected data₁And column boy
Do time t₀And the capacity factor k₁To k₁= (T₁-T₀₁) / T₀₁  Ask by.

Next, as shown in FIG.
Φ_TwoAnd the same measurement is performed, and the capacity factor k_TwoAsk for
You. k_Two= (T_Two-T₀₂) / T₀₂  It is.

Next, as shown in FIG. 7, the slope S is calculated from the obtained capacitance factors k ₁ and k ₂ and the compositions Φ ₁ and Φ ₂ as S = (log k ₁ −log k ₂ ) / (Φ ₂ − Φ ₁ ), and the intercept logk ₀ corresponding to extrapolating the B solution concentration to 0 is calculated by logk ₀ = (Φ ₂ logk ₁ −Φ ₁ logk ₂ ) / (Φ ₂ −Φ ₁ ). Then, it outputs the gradient S and intercept log k ₀ by the printer.

Further, when the CPU 52 can identify the peak component,
As shown in FIG. 8, from the measured data, the retention time of the target peak component in the eluent of any composition, for example, t ₁ is compared with the retention time of the eluent in the setting section, and the retention time is used to calculate select become candidate substances, the closest gradient S and intercept log gradient S and intercept log k ₀ obtained in FIG. 7
A substance having k ₀ is set as a target component, and the result is output by a printer.

[0017]

[Effect of the Invention] In the present invention, in order to identify the peak component of a liquid chromatograph, and besides by varying the eluent composition of the retention times to calculate the characteristic log k ₀ and S, used in means of the peak component identification As a result, k ₀ and S can be used in addition to the retention time as a qualitative quantity specific to a certain peak component, and the amount of information for identification increases and the reliability of identification increases.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing the present invention.

FIG. 2 is a diagram showing a change in retention time due to different eluent compositions.

FIG. 3 is a diagram showing a relationship between a capacity factor and a concentration of an eluent.

FIG. 4 is a configuration diagram showing one embodiment.

[5] B solution concentration is a flow chart for determining the capacity factor in [Phi ₁ eluent.

FIG. 6 is a flowchart for obtaining a capacity factor in an eluent having a B solution concentration of Φ ₂ .

FIG. 7 is a flowchart for obtaining a characteristic S, log k ₀ from the obtained capacity factor.

FIG. 8 is a flowchart for performing identification based on the obtained characteristic S, log k ₀ and the holding time.

[Explanation of symbols]

 12, 14 Solvent 16, 18 Liquid sending pump 22 Injector 24 Column 26 Detector 28, 30 Flow control unit 32 Concentration setting unit 34 Data input unit 36 Data storage unit 38 Capacity factor calculation unit 40 Characteristic value calculation unit 42 Calculation result output unit 44 holding time setting section 46 characteristic value setting section 48 identification section 50 identification result output section 52 CPU 54 memory device 56 keyboard 58 CRT 60 printer

Claims (2)

(57) [Claims] 1. A liquid chromatograph having a sample injection part in a flow path for supplying an eluent to a column and having a detector for detecting a sample component from the eluate from the column, wherein two types of solvents are used as eluents. A liquid feeding system capable of changing the mixing ratio of these solvents to at least two types, a control unit thereof, a data storage unit for storing chromatogram data in an eluent of each mixing ratio, and a data storage unit. A capacity factor calculator for calculating the capacity factor k of the target peak component from
And a characteristic value calculator for calculating k ₀ and the slope S of the target peak component, assuming that log k = log k ₀ −SΦ (Φ is the concentration of one of the solvents) is satisfied. 2. A retention time setting section for storing a retention time of a peak component in an eluent of each mixing ratio, and a characteristic value setting for storing k ₀ and S of a peak component in an eluent of each mixing ratio. and parts, as compared with k _0, S retention time retention time obtained from the data storage unit for the purpose peak component and characteristic value k _0, hold the S time setting unit that is calculated by the arithmetic unit and the characteristic value setting section The liquid chromatograph according to claim 1, further comprising an identification unit for identifying a target peak component.