JPH1123547A - Sampling loop for liquid chromatograph and liquid chromatograph - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the sticking of a blood component and take stable measurement by covering the inner surface of a metal or resin sampling loop with a fluororesin film. SOLUTION: Stainless steel or a PEEK resin is used for a metal or resin sampling loop, and is covered with polytetrafluoroethylene by powder baking for a fluororesin film, for example. When the thickness of the fluororesin film is made too thin, the adsorption preventing effect of a blood component becomes insufficient. When the thickness is made too thick, the inner diameter of the sampling loop is reduced, and the thickness is set to about 5-30 μm. Since the inner surface is covered with the fluororesin film, the sticking of the blood component to the inner surface can be suppressed, the measured value is stable from the initial stage of measurement, and the blood component is hardly stuck over a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sampling loop for a liquid chromatograph and a liquid chromatograph incorporating the sampling loop.

[0002]

2. Description of the Related Art In the field of clinical testing, components in blood samples are separated and quantified by liquid chromatography. Such a liquid chromatograph is usually constituted by an apparatus as shown in FIG. That is,
It comprises an eluent container 1 in which the eluent 11 is accommodated, a liquid sending pump 2 for sending the eluent 11, a sample introduction device 3, a separation column 4, a detector 5, and a pipe connecting each.
The sample introduction device 3 generally includes ports a, b, c, d,
The injection valve 6 comprises a six-way valve having e and f, a sampling loop 7 connected between the ports cd of the injection valve 6, a sample aspirator 8, a sample container 9, and a pipe connecting each of them.

In order to separate a sample using the above-described liquid chromatograph, a port e of an injection valve 6 is used.
-C, ab, df connected (shown by solid lines in Fig. 1)
The eluent 11 enters the separation column 4 via the port ab of the injection valve 6 by the liquid sending pump 2 and is then discharged outside the apparatus as a drain through the detector 5. . On the other hand, the sample is sucked from the sample container 9 by the sample aspirator 8, passes through the ports ec of the injection valve 6, and fills the sampling loop 7.

In this state, the injection valve 6 is switched, and the ports ac of the injection valve 6,
ef and db are connected (shown by a broken line in FIG. 1). As a result, the sample in the sampling loop 7 is pushed by the eluent 11 and passes through the port db, so that the separation column 4
And each component in the sample is separated by the separation column 4. Each of the separated components is detected by the detector 5, for example, by measuring the absorbance, and the result is represented as a chromatogram (not shown).

In the above liquid chromatograph, the material constituting the sampling loop 7 is made of a metal such as stainless steel, or polyether ether ketone (PEEK), which is less likely to adsorb proteins and the like than metals.
Resin (such as resin)
There is a semi-micro column high-performance liquid chromatograph manufactured by Shiseido Co., Ltd., trade name "NANOSPACE SI-1").

However, since the sampling loop has the longest contact time with the blood sample in the piping of the liquid chromatograph, proteins and the like in the blood are easily adsorbed, and when the adsorbed substances accumulate, the flow rate decreases and the pressure increases. This may cause inaccurate measured values or cause equipment failure. That is, in the metal loop, the performance of preventing blood components from being adsorbed is insufficient, and blood components are likely to accumulate and clog the pipes. In addition, a loop made of an inert resin such as PEEK resin has a sufficient ability to prevent blood component adsorption. However, when a new loop is attached to the apparatus and measurement is started, the measured value at the beginning of the measurement is unstable. There was a disadvantage that it fluctuated.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method in which after a sampling loop is attached to an apparatus, measured values are stable from the beginning of measurement, and An object of the present invention is to provide a liquid chromatograph sampling loop and a liquid chromatograph in which components are difficult to adhere over a long period of time.

[0008]

A sampling loop for a liquid chromatograph according to the present invention is a sampling loop in a sample introduction device of a liquid chromatograph for analyzing a blood sample, wherein the inner surface of a metal or resin sampling loop is formed. It is characterized by being coated with a fluororesin film.

[0009] A liquid chromatograph of the present invention is characterized in that the above-described sampling loop for liquid chromatograph of the present invention is incorporated therein.

In the sampling loop for a liquid chromatograph of the present invention, the inner surface of a metal or resin sampling loop is covered with a fluororesin coating.

As the metal of the metal sampling loop, any metal conventionally used for a sampling loop can be used, for example, stainless steel.

As the resin of the sampling loop made of the resin, any of the resins conventionally used for the sampling loop can be used. For example, an inert resin such as PEEK resin described in the section of the prior art can be used. Resins.

The fluororesin film is not particularly limited as long as it is a film made of a fluororesin, and examples thereof include a film obtained by baking powder of polytetrafluoroethylene or the like. The thickness of the coating is preferably 5 to 30 μm, because the thinner the coating, the less the effect of preventing blood components from adsorbing, and the larger the coating, the smaller the inner diameter of the sampling loop, which adversely affects the measured values of the blood components.

[0014]

In the sampling loop of the present invention, since the inner surface is coated with the fluororesin film, the adhesion of blood components to the inner surface can be suppressed. The measured values are stable and blood components are difficult to adhere to over a long period of time.

Since the liquid chromatograph of the present invention incorporates the liquid chromatograph sampling loop of the present invention, after the sampling loop is attached to the apparatus, the measured values are stable from the beginning of the measurement, and the blood components are reduced. It is difficult to adhere for a long time.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to examples.

Example 1 An inner surface of a sampling loop made of stainless steel having an inner diameter of 0.5 mm was coated with a fluororesin by a powder baking coating method.
A film having a thickness of about 10 μm was formed to obtain a sampling loop of the present invention.

Comparative Example 1 Example 1 was repeated except that no fluorine resin film was formed.
Is the same as the sampling loop of FIG.

Comparative Example 2 This is a sampling loop made of PEEK resin (manufactured by GL Sciences) having an inner diameter of 0.5 mm.

Performance test "H" commercially available as a liquid chromatograph for measuring human hemoglobin A1c, manufactured by Kyoto Daiichi Kagaku Co., Ltd.
Using a liquid chromatograph having the sampling loop of Example 1, Comparative Example 1 or Comparative Example 2 attached to the sampling loop portion of "i-Auto A1c", heparin was added as a measurement sample immediately after blood of a healthy person was collected. The sample was diluted and lysed 290-fold with 21 L of dedicated hemolysis (phosphate buffer containing a nonionic surfactant) attached to the above device, and the eluent was used as the eluent. The hemoglobin analysis of human blood was repeated for 15,000 samples, and the total area of peaks appearing in the chromatogram was measured for each measurement. Measurement start 1
Specimens, 3800, 9600 and 1500
Table 1 shows the total area of the peak of the 0th sample.

[0021]

[Table 1]

The total area of the peaks is proportional to the internal volume of the sampling loop, and the total area of the peaks decreases because blood components adhere to the inner surface of the sampling loop and accumulate and reduce the internal volume. Things. Table 1
As a result, in Comparative Example 1, the total area of the peaks gradually decreased, and measurement became impossible at the 9600th sample due to an increase in the piping pressure of the apparatus. This is probably because blood components accumulated in the sampling loop and clogged.
In Example 1 and Comparative Example 2, measurement was possible even at the 15,000th sample, and it is considered that blood components hardly accumulated in the sampling loop.

Next, the stability of the total area of the peaks at the beginning of the measurement after the sampling loop was newly incorporated into the apparatus was compared. The results are shown in Table 2.

[0024]

[Table 2]

As a result, in Comparative Example 2, the total area of the peaks was 5
Although there is a difference of about 2800 in the specimens, the difference between Comparative Example 1 and Example 1 is within 500, indicating that the measured value is more stable. This is probably because the blood component adhered to the resin surface in the early stage of the measurement in the PEEK resin of Comparative Example 2.

[0026]

The structure of the sampling loop for a liquid chromatograph of the present invention is as described above. In the liquid chromatography measurement, the measured value is stable immediately after the sampling loop is incorporated. The period can be extended more than twice as long as before.

The structure of the liquid chromatograph of the present invention is as described above. In the liquid chromatography measurement, the measured value is stable immediately after the sampling loop is incorporated, and the period from the disassembly of the sampling loop to the washing is reduced by the conventional two. Can be extended more than twice.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a liquid chromatograph.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Eluent container 11 Eluent 2 Liquid sending pump 3 Sample introduction device 4 Separation column 5 Detector 6 Injection valve 7 Sampling loop 8 Sample aspirator 9 Sample container a, b, c, d, e, f port

Claims (2)

[Claims] A sampling loop in a sample introduction device of a liquid chromatograph for blood sample analysis, wherein an inner surface of a metal or resin sampling loop is coated with a fluororesin coating. Graph sampling loop. 2. A liquid chromatograph, wherein the liquid chromatograph sampling loop according to claim 1 is incorporated.