JPH01107158A - Flow injection analyzing method - Google Patents

Abstract

PURPOSE:To make it possible to perform highly accurate analysis quickly, by sending sample solution and reagent solution through flow lines independently, sending both solutions into a mixing flow line by specified amounts alternately, and mixing the solutions so as to react each other. CONSTITUTION:Sample solution and reagent solution are alternately sent to a mixing flow line by minute amounts through independent flow lines C1 and C2. The contact areas of both solutions are made large, and the solutions are mixed. As a pump used for this purpose, a non-pulsating-flow double-plunger type pump is suitable. A plunger for the sample solution line C1 and a plunger for the reagent solution line C2 are not synchronized. The amount of discharged solution per stroke is adjusted at about 5mul. Thus, the reaction rate in an flow injection analysis can be brought to 100% indefinitely. The reaction rate can be kept constant all the time. Since extra reagent and the like are not used, the method is economical.

Description

Detailed Description of the Invention (a) Technical Field The present invention relates to a quantitative analysis method for quantitatively determining the chemical composition of a substance, and more specifically relates to a flow injection analysis method (hereinafter referred to as FIA). It is about improvement.

That is, a sample solution and a reagent solution are introduced into a corrosion-resistant tube, such as a Teflon tube, in an amount of 1/2 to cause a reaction, and the physical or chemical properties of the reaction product are used for measurement in a flow cell. This invention relates to the improvement of analytical techniques for determining the target chemical components in a sample (mostly photometric methods).

(B) Background Art The main wet chemical analysis methods for quantifying the amounts of component substances constituting a sample include heavy liquid analysis, volumetric analysis, and spectrophotometry.

In gravimetric analysis, the target component is separated as a 100% insoluble precipitate and then weighed for quantitative determination, while in volumetric analysis and spectrophotometry, a reagent solution of a known concentration is added to the solution of the target component. Let it work.

The content of the target component is calculated by determining the point or absorbance at which 100% of the reaction occurs.

In the spectrophotometric analysis method, the following conditions are required: the reaction proceeds quantitatively and does not involve side reactions, and the completion of the reaction can be quickly and clearly determined.1 The reaction rate is fast.

Also in this spectrophotometric analysis, the target component was measured at 100%
It is quantified by measuring its absorbance as a completely colored compound.

In this way, the basic idea of quantitative analysis is to limit the number of target components to 1.
It is essential to quantify after reacting to nearly 00%.

However, FIA is easy to operate and is suitable for analyzing multiple samples.For example, a reagent solution and a sample solution are mixed and reacted in an ultra-thin Teflon tube to generate a reaction product. Because the residence time of
In most cases, the reaction is not completely completed and is still in the middle of the reaction.

At present, a complete quantitative analysis has not been conducted.

In view of the problems of the conventional FIA, the present invention has been developed (tT)
The basic idea is to make the reaction rate of FIA infinitely close to 100%, and ■ to keep the reaction conditions constant so that even if the reaction rate does not reach 100%, a constant reaction rate close to 100% can be obtained. It was developed as a design concept.

(C) Disclosure of the Invention The present invention solves the above-mentioned problems of FIA and provides an applied technology using a flow line set W that enables more accurate quantification. This is an improved version.

(a) Sample solution and reagent solution are alternately fed in minute amounts, and both solutions have a larger surface area in a narrow reaction tube.
To increase the reaction rate by making liquid contact and mixing sufficiently.

(b) Keeping the reaction rate constant by keeping the flow rates of the reagent solution and sample solution constant and the reaction temperature constant.

Therefore, in the method of the present invention, the sample solution and the reagent solution are passed through independent flow lines, and then a small predetermined amount of each solution is alternately sent to the mixing flow line for mixing and reaction. .

In addition, at least a portion of the old mixing flow line passes through a constant temperature bath to maintain a predetermined temperature to maintain a constant reaction rate, and a back pressure coil is connected to the rear of the flow cell to prevent the generation of bubbles. At the same time, a flow with less pulsation can be obtained.

Although it is preferable to keep the amount of sample solution and reagent solution as small as possible, the accuracy of the flow rate of the pump for liquid delivery is important.

Due to various factors such as the viscosity of reagents and sample solutions 9 and the accuracy of the inner diameter of the reaction tube, the inner diameter of the flow line and the optimal range of the amount of liquid to be fed are naturally limited.

That is, the inner diameter of the flow line tube is 0.25e++s
If it is less than 1-t, not only will the flow resistance between the inside of the tube 1-t and the solution become high, and the internal pressure will become high, but also the sample solution and reagent solution will not be sufficiently mixed. Furthermore, if the inner diameter exceeds 1.0 mm, the flow resistance inside the tube will decrease, and at the same time the internal pressure will also decrease, making it easier to manufacture and handle the device, but this may result in the consumption of more reagents and samples than necessary. The cost will be high.

On the other hand, once the inner diameter of the tube is determined, the maximum amount of A-waves is naturally limited to a certain range.In particular, it is necessary to alternately feed the fine sewing liquid to the mixing/reaction line with high precision and to maintain a high and constant reaction rate. (2) If the batch liquid feeding amount is less than 1.25 JL1, the liquid feeding accuracy will be poor, and if it exceeds 20 JL1, there is a risk that the mixing of the reagent solution and sample solution will be insufficient.

Therefore, the inner diameter of the independent flow lines for the sample solution and the reagent solution is preferably 0.25 to 1.0 mo+, and the reagent solution to be alternately fed to the mixed flow line for both solutions is 1.
．． 25 to 208 Ll is preferred.

Next, one embodiment of the method of the present invention will be described in detail with reference to the drawings.

(d) Example FIG. 1 shows an example of a flow path diagram in the present invention, and FIG. 2 shows a liquid feeding state of a mixing flow line.

As mentioned above, in the method of the present invention, the sample solution C,/ and the reagent solution C,/
The two liquids are fed into the mixing flow line alternately in small increments as shown in Figure 2, increasing the contact area of both liquids and mixing.

Therefore, a non-pulsating flow double plunger type pump is suitable as the pump P to be used, and the amount of liquid discharged per stroke can be controlled without synchronizing the plunger for the sample solution line C1 and the plunger for the reagent solution line C2. Approximately 5JLJ
Check it so that it becomes l. In the case of a Teflon tube with an inner diameter of 0.51 cm, this volume corresponds to a liquid length of about 25 cm. Further, in order to obtain a constant flow rate without pulsation, a double plunger type pump with different phase difference is preferable, for example, a pump with a stroke length of 11111, a stroke discharge amount of 51L1, and a plunger diameter of about 2 to 3III is desirable.

B in the figure is a hexagonal injection valve for sample injection provided in the sample solution line C1, where the sample S is pressurized into the carrier liquid.

RC is a reaction coil in which both liquids are mixed and reacted. In this case, the reaction coil RC is installed in a constant temperature bath HB, and the reaction temperature of both liquids C,/ and 02' is kept constant to increase the reaction rate and to keep the reaction rate constant.

Next, the reaction solution that has been sufficiently reacted in the reaction coil RC in the mixing flow line is sent to the flow cell FC and measured by spectrophotometry or the like, and the measurement 18 is recorded on the recorder R.

On the other hand, the liquid in the m-scrabble is transferred to the back pressure coil RPC (
For example, an inner diameter of 0.20 to 0.50 mm) is passed through L-' (wasted outside the line. This waste liquid W is discharged after being subjected to IF treatment at the time of pollution.

The back pressure coil RPC prevents the generation of bubbles in the entire flow line and is useful for obtaining a stable steady flow without pulsation.

Generally, a pelister type pump is sometimes used to maintain a pulsating flow in the flow line, but this type of pump has poor durability, so a plunger type pump is preferred as described above. is preferred.

Note that the present invention is of course applicable not only to the flow injection analysis method but also to many other flow line analysis methods.

(e) Effects of the Invention According to the present invention, the reaction rate of FIA can be brought infinitely close to 100%, and the reaction rate can be constantly kept constant, so analysis with extremely high precision can be performed quickly. It has advantages such as being economical because it does not require the use of unnecessary reagents, etc.

[Brief explanation of the drawing]

FIG. 1 is an example of a flow path diagram based on the method of the present invention.
The figure is an explanatory diagram showing a liquid layer state diagram in a mixing flow line in the method of the present invention. Code explanation C3-sample solution line C2-reagent solution line C,/
- Sample solution C9' - Reagent solution P - Non-pulsating flow double plunger pump S - Sample B - Six-way injection valve M - Mixing joint RC - Reaction cell FC - Flow cell R - Recorder W - Waste liquid HB - Constant temperature bath patent Applicant Dowa Mining Co., Ltd. Representative Patent Attorney Asaga
-Husband: patent attorney Asaga - Itsuki

Claims (4)

[Claims] (1) Flow injection analysis characterized by passing a sample solution and a reagent solution through independent flow lines, and then alternately feeding a predetermined amount of both solutions to a mixing flow line for mixing and reaction. Law. (2) The inner diameters of the flow lines for the sample solution and the reagent solution are each 0.25 to 1.0 mm, and the predetermined amounts of the two solutions that are alternately fed are both 1.25 to 20 μl.
A flow injection analysis method according to claim 1. (3) The flow injection analysis method according to claim 1 or 2, wherein at least a portion of the mixed flow line passes through a constant temperature bath. (4) The flow injection according to claim 1, 2 or 3, wherein a back pressure coil is connected to the rear part of a flow cell provided at the end of the mixing flow line to adjust the internal pressure of the flow line. Analysis method.