JPH0363565A - Liquid chromatograph - Google Patents

Abstract

PURPOSE:To automatically judge the timing for starting an analysis operation by emitting an analysis start signal when the fluctuation width of a base line falls to a decision level or below. CONSTITUTION:The base line detection time (t) and the base line decision level level A are inputted from a constant setting section. A base line fluctuation detecting section 22 takes in the detection signal from a detector 10 only for the time (t) and compares the difference between the max. value and the min. value thereof with the decision level A. The detecting section further takes in the detection signal for the next time (t) and repeats the same operation when the decision level A is exceeded. The detecting section sends the analysis start signal to a system controller 18 by deciding that the system is stabilized when the signal falls down to the decision level A or below.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid chromatograph, and more particularly to a liquid chromatograph equipped with a system controller for controlling analysis operations.

(Prior Art) Some liquid chromatographs are equipped with a system controller that preprograms analysis conditions such as changing the composition of an eluent such as in gradient analysis and controls analysis operations according to the program. The system controller is the liquid pump that makes up the liquid chromatograph,
This device controls the temperature of the detector, sample injector, column oven, etc., and enables automatic analysis.

The liquid chromatograph must be stable when the system controller begins controlling analytical operations. Whether it is stable or not can be determined based on the baseline of the detector. In order for the baseline to be stable, conditions such as stable column temperature, stable pump operation, complete replacement of the eluent with the target eluent, and stable detector are required. It takes time for the baseline to stabilize, and up until now, the detection signal from the detector has been recorded on a recorder, and the operator has judged whether the baseline has stabilized by looking at the results.

(Problem to be solved by the invention) The system controller is for automating the operation of the liquid chromatograph, but the operator must ensure that the liquid chromatograph is stable until the system controller starts controlling the analysis operation. Since it is necessary to determine whether or not the period is the same, that period cannot be automated.

Therefore, the present invention adds a function to automatically determine whether or not the baseline has stabilized by capturing the baseline detection signal of the detector, so that analysis operation can be started automatically when the baseline is stabilized. The purpose of this invention is to provide a liquid chromatograph that can

(Means for solving problems) The present invention will be explained with reference to FIG.

10 is a detector, 18 is a system controller that controls the analysis operation, and 26 is an analysis start control unit that causes the system controller 26 to start controlling the analysis operation after detecting that the baseline of the detector has become stable. The analysis start control unit 26 inputs the baseline signal from the constant setting unit 20 that sets the baseline detection time and the baseline judgment level hole, and the detector 10, and determines the maximum value and minimum value of the detection signal at the detection time. A baseline fluctuation range detecting unit 22 that calculates the difference between the baseline fluctuation range and the detected baseline fluctuation range is compared with the determination level A, and when the baseline fluctuation range becomes equal to or less than the determination level A, an analysis start signal is sent to the system controller. A comparing section 24 is provided.

(Function) A baseline detection time and a baseline judgment level hole are previously set in the constant setting section 20 using a keyboard or the like.

As shown in Figure 2,! & Initially, the liquid chromatograph system is operated under baseline measurement conditions (step 35), at this time the system controller is not yet controlling according to the program, and the flow rate and composition of the eluent are kept constant. .

From the constant setting section 20, input I'IIff at the time of baseline detection and the baseline judgment level hole (steps S2 and S3), and set T=O (step S4). The baseline fluctuation range detection unit 22 takes in the detection signal from the detector 10 for a time t, and the maximum value Imax and the minimum value lm during that time.
1n is detected and the difference (Imax - lm1n) is calculated (step 35). The comparison section 24 calculates the difference (Ima
x −lm1n ) and the determination level A input from the constant setting unit 20 (step S6). The difference (im
If ax - lm1n ) has not become below A, the system is not yet stable, so the detector signal is captured for the next time t, and in the same way, the difference between the maximum and minimum values for that period is determined. Compare with A again (step S7
．． S5. S6). If the difference between the maximum and minimum values of the baseline (Imax-Imin) during period t becomes equal to or less than A, the system is stable, so a signal is sent to the system controller 18 to start an analysis operation according to the program. (Step 35).

(Example) FIG. 3 represents one embodiment.

Reference numeral 2 denotes a liquid pump that sends the eluent 4 to the column 8.

When performing gradient analysis, multiple types of eluents are prepared, and multiple pumps may be used to adjust the composition and flow rate of the eluent according to the program. An injector 6 is provided to automatically inject a sample into the flow path of the eluent sent out from the pump 2. The effluent from column 8 is guided to detector 10 and detected.

A detection signal from the detector 10 is sent to a data processing device 14 . A recorder 6 is connected to the data processing device 14 . A column oven 2 controls the temperature of the column 8.

18 is a system controller, which includes a pump 2, an injector 6, a column oven 12, and a data processing device 14.
The analysis operation is automatically controlled according to pre-programmed analysis conditions.

In this example, the analysis start control unit 2 shown in FIG.
6 is realized using, for example, a CPU and a memory device included in the system controller 18. Therefore, the detection signal of the detector IO is also. A signal line 30 is used to input the analysis start control unit formed in the system controller 18 .

The function of the analysis start control section 26 can also be realized in the data processing device 14. Therefore, in another embodiment, the analysis start control section 26 is implemented using the CPU and memory device of the data processing device 14.

In this case, the signal line 30 from the detector 10 to the system controller 18 is no longer necessary, and the baseline detection signal from the detector IO may be taken in using the detection signal line connected to the data processing device 14. A signal line 32 is provided for sending an analysis start signal from an analysis start control section formed in the data processing device 14 to the system controller 18.

(Effects of the Invention) The liquid chromatograph of the present invention is equipped with an analysis start control section that detects when the baseline of the detector has stabilized. In contrast, in the present invention, it is possible to automatically determine when to start the analysis operation, and further automation can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the present invention, FIG. 2 is a flowchart 1 to 1 to show the operation of the present invention, and FIG. 3 is a block diagram showing one embodiment. 10...Detector, 18...System controller, 20...Constant setting section, 22...
. . . Baseline fluctuation range detection section, 24 . . . Comparison section, 26 . . . Analysis start control section.

Claims (1)

[Claims] (1) A liquid chromatograph equipped with a system controller that controls analysis operation, including an analysis start control unit that starts analysis operation control by the system controller after detecting that the baseline of the detector has become stable;
This analysis start control section includes a constant setting section that sets a baseline detection time and a baseline judgment level A, and a constant setting section that inputs the baseline signal from the detector and determines the difference between the maximum value and the minimum value of the detection signal at the detection time. a baseline fluctuation range detection unit that calculates the baseline fluctuation range, and a comparison unit that compares the detected baseline fluctuation range with determination level A and sends an analysis start signal to the system controller when the baseline fluctuation range becomes equal to or less than determination level A. A liquid chromatograph characterized by comprising: