JP2903107B2 - Chromatography differential signal detection method and detection device used therefor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved method for accurately detecting and quantifying each component in chromatography such as gas chromatography and liquid chromatography, and an apparatus used therefor.

[0002]

2. Description of the Related Art Gas chromatography using an inert gas as a mobile phase and liquid chromatography using an inert solvent as a mobile phase have been known as chromatographys. Using a porous adsorbent such as silica gel and alumina as the phase, eluted with a solvent,
Adsorption chromatography that analyzes the components by the difference in their adsorption power, partition chromatography that analyzes the components by the difference in the partition ratio between the mobile phase and the liquid of the stationary phase, ion exchange chromatography that uses an ion exchanger as the stationary phase, Gel permeation chromatography using a porous gel as a stationary phase is known.

[0003] All of these chromatographies are carried out by continuously detecting and recording the components that have been transferred from the stationary phase to the mobile phase. For example, in liquid chromatography, as shown in FIG. 4, a mobile phase, that is, an eluent is supplied from a mobile phase storage tank 1 by a liquid sending pump 2, and a sample introduced from a sample inlet 3 is carried to carry out a separation column. Each component in the mobile phase which is adsorbed on the mobile phase 4 and subsequently eluted is detected by the detector 5, and a signal corresponding to the elution time and the amount of the component at this time is recorded in the recorder 9.

[0004] As described above, the conventional chromatography uses one detector, detects the concentration of each component as a function of the elution time, and estimates and quantifies the type of the component based on the signal. ing.

[0005]

In the conventional chromatography, the signal obtained from the detector is a direct representation of the change in concentration with respect to time, and is therefore contained in high-purity substances. Signals of trace impurities and substances having similar elution times often have overlapping signals, which makes it difficult to obtain accurate information.

[0006] It is an object of the present invention to separate a small signal wrapped in such a large signal or a signal integrated in a duplicate manner, and to analyze and quantify it more accurately and more precisely. It was done.

[0007]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for accurately analyzing and quantifying trace components in a sample and substances having similar elution times in chromatography. By using at least two detectors the information signal obtained by
It has been found that the problem can be solved by detecting and recording a differential signal by providing a phase difference therebetween, and based on this finding, the present invention has been accomplished. Heretofore, it has not been known at all about performing accurate and accurate analysis using such differential signals in chromatography.

That is, the present invention relates to a chromatography for continuously detecting and recording an analytical component by continuously sending a mobile phase solvent to a sample adsorbed on a separation column and separating and eluting the analytical component from the separation column. A method for detecting a differential signal in chromatography and a mobile phase storage unit, wherein a differential signal is obtained at least twice by providing a phase difference therebetween, a differential signal is obtained from each output, and a component is recorded based on the differential signal. In a chromatography apparatus in which a liquid unit, a sample injection unit, a separation adsorption unit and a detection unit are connected in series, and information from the detection unit is input and recorded in a recording unit, the phase difference between the detection units is determined. And at least two detectors that are provided and differential, and the recording unit is configured to record the output from each detector as a differential signal. There is provided a chromatographic device according to symptoms.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the present invention will be described with reference to the accompanying drawings. 1 is a system diagram in the case where the present invention is carried out using three detectors 5, 5 ', 5 ". In FIG. 5 ', is detected simultaneously by 5 ", is outputted as a signal ^{A 1, A 2, A 3} . In this example, the signal is converted into a voltage and output. At this time, 'the chromatographic signals than A, time lag of Delta] t, i.e. generate a phase difference, the detector 5 Signal A ¹ of the detector 5 is the same content after Delta] t time' and the detector 5 5 signals the a ^2.

[0010] Therefore, to process the voltage of the output A ¹ and A ² in the differential amplifier 6, and outputs as a signal B ^1, this signal B ¹ represents would give the first derivative signal. Similarly the detector 5 'and a voltage of 5 "differential amplifier 6' is treated output in a first-order derivative signal B ² is obtained.

Next, the signal B thus obtained is
By treatment with ¹ and the differential amplifier 7 to the voltage of the B ^2, it is possible to obtain the second derivative signal C ^1. Hereinafter, an arbitrary n-th differential signal can be obtained in the same manner.
The information thus obtained is finally recorded on the recorder 9.

As the detector in the present invention, a detector conventionally used in chromatography can be used as it is. Examples of such detectors include ultraviolet / visible detectors, infrared spectroscopy detectors, differential refractive index detectors, fluorescence detectors, ultraviolet multi-wavelength detectors, electrical conductivity detectors, electrochemical detectors, lasers Detectors, inductively coupled high frequency plasma emission detectors, streaming potential difference detectors, and the like. Signals obtained from these detectors can be converted into, for example, voltage signals and output as differential signals using the above-described differential amplifier.

In addition, as the mobile phase storage tank, liquid feed pump, sample introduction mechanism, separation column, recorder and the like used in the present invention, those commonly used in known chromatography apparatuses can be used as they are. The analysis conditions do not need to be changed at all, and can be performed under the same conditions as in the conventional case.

[0014]

Next, the present invention will be described in more detail by way of examples.

Example 1 Liquid sending pump (GL Science, model 576), 20
Injector with Rh loop (Rheodyne model 7125), octadecylsilyl-silica gel column 4.6 mm in diameter and 50 mm in length (Fuji Cereal Chemical,
Eluent at room temperature using a liquid chromatography apparatus composed of two UV detectors (SPD6AV manufactured by Shimadzu Corporation), a differential amplifier and a recorder (U228 manufactured by Shimadzu Corporation), particle diameter 5 μm, pore diameter 100 mm) A liquid chromatographic analysis was performed using pure benzene and benzene containing 25% by weight of benzene impurities as a sample at a wavelength of 254 nm under the conditions of a flow rate of 1 ml / 1 minute using an equal volume mixture of water and acetonitrile. . As an example of the benzene impurity, an impurity having a difference of 5 seconds between benzene and a retention time (time from sample introduction to signal detection) is assumed, and 100 μg / acetonitrile is added to each of two sample introduction sections connected in series. After adding 20 μl and 5 μl of benzene dissolved at a concentration of ml, the first sample introduction section was opened, and 5 seconds later, the second sample introduction section was opened to obtain an impurity signal.

The first derivative signal of benzene obtained in this manner is shown as (b) in FIG. (A) is the same benzene signal when analyzed with a conventional measuring device for comparison. Retention time about 3 for both signals
Minutes and 30 seconds.

FIG. 3 (a) shows a signal obtained by analyzing a sample containing a benzene impurity with a usual measuring device. According to this, a signal of an impurity appears as a shoulder at an elution time of 5 seconds behind benzene. (B) is a first derivative signal when analyzed according to the present invention, and is observed in a state where the signal of the impurity is clearly separated. The differential amplifier used in this example is a self-produced work that can measure from 1 mV to 10 V with a time constant of about 1 ms.

Example 2 The flow rate under the conditions of liquid chromatography analysis was 1 ml / 1
The analysis was conducted in the same manner as in Example 1 except that the amount was changed from 1.5 minutes to 1.5 ml / 1 minute. Retention time is about 2 minutes 20 minutes
Except for the second, almost the same results as in Example 1 were obtained.

[0019]

According to the present invention, it is possible to accurately analyze and quantitate a trace component or a component having an approximate elution time which could not be identified due to overlapping peaks in the conventional chromatography.

[Brief description of the drawings]

FIG. 1 is a system diagram for explaining a method and an apparatus of the present invention.

FIG. 2 shows signals of pure benzene in the conventional method and the method of the present invention.

FIG. 3 shows signals of benzene containing impurities in the conventional method and the method of the present invention.

FIG. 4 is a system diagram for explaining a conventional method and apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mobile-phase storage tank 2 Liquid-sending pump 3 Sample inlet 4 Separation column 5, 5 ', 5 "Detector 6, 7, 8 Differential amplifier 9 Recorder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 30/86 G01N 30/78

Claims (2)

(57) [Claims] 1. A chromatography in which a mobile phase solvent is continuously fed to a sample adsorbed on a separation column, and an analytical component is separated and eluted from the separation column to be continuously detected and recorded. A differential signal is obtained from each output at least twice, a differential signal is obtained from each output, and a component is recorded based on the differential signal. 2. A chromatography apparatus in which a mobile phase storage section, a liquid sending section, a sample injection section, a separation and adsorption section and a detection section are connected in series, and information from the detection section is inputted and recorded in a recording section. The detection unit is configured with at least two detectors that provide a phase difference between each other to make a difference, and the recording unit is configured to record an output from each detector as a differential signal. Chromatography apparatus.