JPH0552832A - Gas chromatograph - Google Patents

Abstract

PURPOSE:To automatically judge whether an analyzing operation possible state is achieved at the time of the start of operation by providing a stability judging part and comparing the change rate of a base line at a definite unit time with a preset judging level. CONSTITUTION:The sampling cycle of a base line detection signal and the judging level of a slope are preset to the constant setting part of a base line stability judging part 30 from a keyboard. When operation is started, a flow sensor 10 judges whether carrier gas is being supplied. When said gas is being supplied, a temp. stability judging part 20 judges whether control temp. is stabilized. After the control temp. is stabilized, a base line detection part 33 starts the taking-in of a base line signal. The change gradient thereof is compared with the judging level of the slope inputted to the constant setting part 31 and, when said gradient becomes the judging level or less, it is judged that the base line is stabilized and this stability signal is sent to a system controller 50 through an analyzing operation start control part 40 to start analysis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas chromatograph, and more particularly to a gas chromatograph equipped with a control unit that automates the stability judgment required at the start of analysis.

[0002]

2. Description of the Related Art Some current gas chromatographs are provided with a system controller that pre-programs analysis conditions and controls the analysis operation according to this program. However, until the operation is started and the analysis operation is started, Few have automatic judgment function for each stability judgment.

Attempted means include indirect means for providing a stable time by a time sequence that can be varied depending on analysis conditions, and a chromatogram data processing apparatus having a system control section for directly inputting a detection signal of a detector. , Connect an external device such as a personal computer,
There are means to make a stable judgment, but all of them are expensive.

[0004]

Generally, in order to stabilize the baseline, the stable supply of carrier gas and the stable temperature of each of the sample introduction part, column, detector, etc. are maintained, and the line is fixed with a fixed amount of carrier gas. It is necessary to replace the detector and stabilize the detector.

It takes time for the baseline to stabilize,
Up to now, the signal from the detector was recorded in a recorder and whether or not it was stable was judged by the person performing the driving operation by looking at the result.

When automating the operation of the gas chromatograph, it is necessary to judge whether the operator is stable or not until the control of the analysis operation is started after the carrier gas is supplied and the power is turned on. Cannot be automated.

[0007]

SUMMARY OF THE INVENTION Therefore, according to the present invention, the carrier gas is supplied, the temperature of each part is stabilized, and the baseline detection signal of the detector is taken in to automatically determine whether the baseline is stable or not. The purpose of the invention is to provide a gas chromatograph that adds a judgment function and can start an analysis operation manually or automatically at a stable time, and judges the supply of carrier gas by a pressure sensor, a flow sensor, etc. The supply determination unit, the temperature stability determination unit that determines the stability of each control temperature of the sample introduction unit, column oven, detection unit, etc., and the baseline signal from the detector is input, and the baseline It has an automatic stability judgment unit that compares and judges the rate of change with a preset allowable value, and an analysis operation start system that automatically starts the analysis operation by the signal of each judgment unit. Parts, characterized in that the allowed connected respectively.

[0008]

The present invention will be described below with reference to the embodiments shown in the drawings. Reference numeral 10 is a supply determination unit including a flow sensor for determining whether or not the carrier gas is supplied, and 20 is determination as to whether or not each control temperature is stable after determining that the carrier gas is supplied. Temperature stability determination unit, 3
Reference numeral 0 is a baseline stability determination control unit that determines whether or not the baseline detection signal from the detector is stable, and detects signals indicating that the above gas supply, temperature stabilization, and baseline stabilization have been completed. After that, a signal is sent to the system controller 50 that controls the analysis operation via the analysis operation start control unit 40 to start the analysis.

A sampling period T of the baseline detection signal, a sampling number m required for slope calculation, a slope determination level A, and a slope determination repetition number n are set in advance in a constant setting section 31 from a keyboard or the like.

As shown in FIG. 2, first, the operation is started, and it is judged by the flow sensor or the like whether the carrier gas is being supplied. If the supply is OK, the heating temperature control of each part and the detector are started. When each control temperature becomes stable, the baseline detection unit 33 starts capturing the baseline signal from the detector at the sampling cycle T.

Assuming that the time of the i-th sampling point of the baseline signal is Ti and the amount of the baseline detection signal at time Ti is Ei, the time of sampling m + 1 time from the time of Ti is Ti + m = Tm,
The detection signal is Ei + m.

The variation gradient Si (hereinafter referred to as slope) of the detection signal at Ti and Ti + m is Si = | (Ei + m−E)
i) / Tm |, the slope value Si is compared with the slope determination level A input to the constant setting unit 31 in the comparison unit 34, and it is determined whether or not it is A or less.

Whether or not the slope S i of the baseline is less than A is determined from S ₀ of the initial value i = O. If it is less than A, then the determination of Si at i = 1 is performed, and sequentially. i
= (N + 1) times repeated determination is performed.

When the slope Si exceeds the judgment level A, the initial value i = 0 is reset, and the slope is judged from S ₀ repeatedly with the next sampling point T ₀ . If the slope Si continuously becomes equal to or lower than the determination level A from i = 0 to n, the baseline is stable, and this stability signal is sent to the analysis operation start control unit to start the analysis.

[Embodiment] FIG. 3 shows an embodiment of the present invention. 3 is an injector for automatically or manually injecting or collecting a fixed amount of the liquid or gaseous sample 1 to be analyzed into the channel of the carrier gas 2 and introducing it into the column 4.
The sample is vaporized, and the heating temperature is controlled to a constant temperature in order to prevent condensation, adhesion, etc. in the channel.

The column 4 is installed in a column oven 8 whose temperature is controlled to be constant. The sample that has flowed into the column 4 is separated into individual components and flows out, and is guided to the detector 5 for detection. The detection signal of the detector 5 is processed by the data processing device 6 and output to the recorder 7.

The system controller 9 incorporates the temperature control of the injector 3, the column oven 8 and the detector 5, and automatically controls the analysis operation according to the preprogrammed analysis conditions.

In the present embodiment, the gas supply determination unit 10, the temperature setting stability determination unit 20, the baseline stability determination control unit 30 and the analysis operation start control unit 40 shown in FIG.
As an example, a CPU provided in the system controller,
Although it is realized by using a memory device and an input / output device,
It can be realized without using a system controller by using a CPU, a memory device, an input / output device provided in the data processing device and separately providing each temperature control unit.

[0019]

EFFECTS OF THE INVENTION The gas chromatograph of the present invention automatically analyzes the supply of carrier gas required to stabilize the line until power is turned on and the analysis is started, the stability of each temperature, and the stability of the baseline for analysis. Since the control unit for starting the operation is provided, the automation of the entire system of the gas chromatograph can be promoted by automating the work conventionally performed by the operator to judge the stability and perform the operation of starting the analysis.

[Brief description of drawings]

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

FIG. 2 is a flowchart showing the operation of the present invention.

FIG. 3 is a block diagram showing an embodiment of the present invention.

FIG. 4 is an enlarged explanatory view of the slope of the baseline of the present invention.

[Explanation of symbols]

 10 Supply Judgment Unit 20 Temperature Stability Judgment Unit 30 Baseline Stability Judgment Control Unit 40 Analysis Operation Start Control Unit 50 System Controller

Claims (2)

[Claims] 1. A supply determination unit that determines the supply of carrier gas by a pressure sensor, a flow sensor, etc., a temperature stability determination unit that determines the stability of each control temperature of a sample introduction unit, a column oven, a detection unit, etc. Equipped with an automatic stability judgment unit that inputs the baseline signal from the instrument and compares and judges the rate of change of the baseline in a certain unit time with a preset constant tolerance value, and the analysis operation by the signal of each judgment unit A gas chromatograph characterized in that an analysis operation start control unit for automatically starting each is connected. 2. A cycle T for sequentially sampling a baseline signal from a detector at regular intervals, a number m of points for obtaining detection signals at a start point and an end point of a constant number of points, and a determination slope required for determination of baseline stability. A constant setting section for setting the level A and the slope determination repetition number n;
The baseline slope detection unit that sequentially samples the baseline signal from the detector to determine the slope is compared with the first detected slope and the judgment level A. If the detected slope is equal to or lower than the level A, then the first slope is detected. It is judged that the start and end sampling points of the slope calculation are shifted by 1 point later and the level is equal to or lower than the level A of the second slope, and in the continuous slope judgment that is shifted by 1 point, it is judged n times in succession. The gas chromatograph according to claim 1, further comprising a comparison unit that determines that the baseline is stable if the level is A or less.