JPS60209173A - Method and device for volumetric analysis by titration - Google Patents

Abstract

PURPOSE:To enable volumetric analysis with good accuracy by delivering a sample and titrating liquid with the same pump using selector valves. CONSTITUTION:Tubes 60-62 are connected to the 1st water tank 35 for washing liquid, a titrating liquid tank 36, the 2nd tank 37 for washing liquid and a sample tank 38. The tanks 35-38 are connected via three-way valves 20, 30-32 and a squeezing type pump 21. A valve 34 is opened by the output signal from a microcomputer of an electronic circuit 100 and water is filled in a reaction vessel 23 for protecting a sensor 9 and is change discharged. A signal is fed to a nozzle driving motor 29 which positions a nozzle 40 to a water discharge tank 26 side and moves the nozzle 40 to the vessel 23 side after checking the output of the pump 21. The pump 21 is run by a prescribed number to feed the sample. The titrating liquid is fed to the vessel 23 by repeating the similar operation and the titration is started. The titration is ended by the microcomputer which checks the signal from the sensor 9. The concn. of the titrating liquid is calculated from the number of revolution of the pump 21 stored in the counter.

Description

[Detailed description of the invention] [Technical field of invention] This invention relates to volumetric analysis such as concentration measurement.

[Prior art]

FIG. 1 is a diagram showing a conventional titration apparatus. The titration operation will be explained below. First, add a predetermined volume of sample (2) to be analyzed.
1 (Defined as Vl) Accurately weigh and put into beaker (1). When the start switch of the control unit (3) is turned on, the piston pump (4) operates and draws the titrant (6) through the tube (7). The piston pump (4) then turns into a pumping action, passing the tube (8) through the beaker (1).
) to the titrant (6). The control unit (3) detects that the reaction has reached the end point based on a signal from a sensor (9) such as a PH meter, and stops the operation of the piston pump (4). The piston pump (4) is equipped with a sliding resistor whose resistance value changes according to the movement of the piston, and the control section (3)
) measures this resistance value at the end point and calculates the volume iV2 of the titrant solution (6) required for titration.

Here, since the concentration N of the titrant (6) is known and the volume v1 of the sample (2) is also measured, the concentration NX of the sample (2) is given by the following equation.

NX=N-ElVl The control unit (3) calculates and displays the concentration of the sample (2) based on this formula.

However, it had the following drawbacks. That is, the first drawback is that it is necessary to accurately know the volume of titrant solution required for titration 1ζ, and therefore high accuracy is required of both the piston pump (4), the sliding movement, and the resistor.

A second drawback is that even if the piston pump (4) or sliding resistor is of high precision, if the precision deteriorates with use of the device, accurate measurements will no longer be possible. Furthermore, the eighth drawback is that the measurement of the sample (2) is carried out by a human, which is inconvenient especially when titrating continuously, and titration cannot be carried out unattended.

1st. To solve the second drawback, a piston pump (4
), it is possible to use a squeezing type pump instead.

Here, the ladder pump refers to a pump that squeezes a tube with a roller or the like to push out a minute amount of liquid.

If a squeezing type pump is used, it is possible to measure the number of squeezes and detect the pushing claw, which eliminates the need for a sliding resistor and solves the problem of increasing the accuracy of the sliding resistor and preventing deterioration. However, since the tube is squeezed, the amount of extrusion changes depending on the type of tube, the duration of use, etc., and there is a new drawback that accurate titration is impossible without constant complicated correction. Ta.

In order to solve the eighth drawback, there is also an apparatus in which the sample (2) is further fed into the beaker using another piston pump. However, these additionally provided piston pumps and sliding resistors are also required to have high precision and high durability, which poses new problems and increases the size and complexity of the device.

[Structure of the invention]

This invention was made for the purpose of solving the drawbacks mentioned in t. It uses a switching valve to push out the sample and the titrant liquid with the same pump, and calculates the concentration based on the ratio of the sample and the titrant liquid required for titration. This paper proposes a method and apparatus for performing capacity analysis.

FIG. 2 is an overall configuration diagram for clearly showing the configuration of the present invention. The valve means (200) communicates one of the sample, the cleaning liquid, and the titration liquid with the flow path, and performs a switching operation in response to a signal from the valve control signal generating means.

The pump (210) provided in the flow path (2) is connected to the nozzle (4).
) to send samples, etc. The nozzle control signal generating means sends a signal to the nozzle switching means to change the position of the tip of the nozzle (2) to switch whether or not to introduce the sample, etc. into the reaction tank (2). Upon receiving the signal from the sensor (9), the end point signal generating means detects the end point of the reaction, provides the end point signal to the pump control signal generating means, and stops the pump (210). A count signal for counting the operation of the pump (210) provides a count signal to the quantitative signal generating means and the calculating means.

The calculation means receives the end point signal and performs eight-quantity analysis.

〔Example〕

Examples thereof will be described below based on the drawings.

In the third cause, the tube @1 → side is the first cleaning liquid water tank (to), the titrant liquid tank, the second cleaning liquid tank @
, is connected to the sample tank to form a flow path. Each tank (to) to so is connected to nozzle 1 via an 8-way valve (a), trough to C1, and a pump e1). As another embodiment, a piston pump or the like may be used for the four levers of the squeezing type pump. A sensor (9) such as a 1wL pH meter is provided inside the reaction tank (2), and a discharge tank (2) is provided outside the reaction tank (2). The nozzle (2) is switched to the inner position (the position shown by the solid line in the figure) or the outer position (the position shown by the broken line) by the nozzle drive motor 4. At the bottom of the reaction tank υ there is an outlet (to),
A valve is provided. Also, the water tank (to) is a tube.

It is also connected to the nozzle (through the valve).

The electronic circuit (100) is a single unit that controls each part, and a case will be described below in which a microcomputer is used, but other embodiments may be constructed without using a microcomputer.

Next, an electronic circuit using a microcomputer (10G
) will be explained with reference to FIG.

The pulse generating circuit generates pulses in accordance with the operation of the straining pump 4. The power inputter η counts these pulses and supplies them to the microcomputer. It is possible to use a microcomputer to perform this function without providing a special counter. The output port selectively gives the output of the CPU 11 to each valve, etc. Note that the use of a digital converter and a D/A converter is a matter of course for those skilled in the art, and therefore illustration thereof is omitted.

Next, the program written in the ROM- is shown in a flowchart as shown in FIG. The operation of the titration device will be explained below according to this flowchart.

When the program starts, the microcomputer wheel first applies a port designation signal to the output port via the signal line, selectively outputs the output signal, and then outputs the output signal to the valve (
to). In this way, the water that filled the reaction tank (2) is discharged to protect the sensor (9). Thereafter, valve (2) is closed (step 70).

Next, send a signal to the nozzle drive motor (2)
is set to the position shown by the dotted line in FIG. 8, that is, to the outer position (step 71). and enough to fill the sample into the tube (into the nozzle)! The displacement pump is rotated (steps 72 and 78). The number of revolutions of the pump to complete filling is fixed and known in advance. Therefore, the CPU 131 checks the output of the counter η so that it rotates a little more. At this time, the excess sample is discharged through the discharge port (2) of the discharge tank. As another embodiment, it is also possible for a phycrocomputer wheel to play the role of the counter (5?j).In yet another embodiment, a sensor that reacts to the sample is provided at the tip of the nozzle to determine filling. It is also possible.

Next, the nozzle head is set to the inside position, and the straining pump is rotated a predetermined number of times (hereinafter referred to as A) to send the sample to the reaction tank (2) (steps 74 and 75).

Thereafter, the same operation as t is repeated to send the titrant to the reaction tank and titration is started (steps 76 to 82). However, if the tube is not washed before sending the titrant into the tube, a reaction will occur with the remaining sample within the tube, making accurate measurements impossible. Therefore, in this embodiment, the tube and nozzle are washed with water (step 7).
8).

The microcomputer checks the signal from the sensor (9) to complete the titration (step 88). When the end point is reached, the straining pump (c) is stopped and the counter η is rotated. number (hereinafter referred to as B) (steps 84 and 85).

The discharge amount per pump revolution varies depending on the age and thickness of the tube, but the variation is so small that it can be ignored within a single measurement period. Therefore, the concentration NX of the sample is given by the following formula, where N is the concentration of the titrant. Calculate based on this calculation formula and display the concentration NX (steps 86 and 87 ”)
.

NX = N hakama (B/A '') Step 88 and subsequent steps are for cleaning the chewing valve ① of the reaction tank (Steps 88 to 91).

In Jin's embodiment, in addition to water, a second cleaning liquid is also used as the cleaning liquid (step 90). For example, when the sample is a phosphoric acid coating treatment solution, it is desirable to use H2SO4 as the second cleaning solution to prevent the sample from adhering to the inside of the tube due to a decrease in concentration. Note that depending on the type of titrant and sample, washing with water may be sufficient, and the washing solution 2 for such cases is not acceptable.

Finally, the reaction tank (2) is filled with water and the process ends (step 92).

In addition, in the scissor gourd and method according to this example, the sample 1M constant solution was sent to the reaction tank (c) in that order, but in other examples, the drawing solution and the sample may be sent to the reaction tank in that order. can.

When a squeeze-type pump is used for a long period of time, the flexibility of the tube changes, and the air delivered during one operation of the pump changes.

However, even if there is such a change, there is no effect since the delivery air for both the sample and the titrant change in the same proportional relationship. In other words, depending on the ratio of the number of simultaneous rotations of the pump? The same effect cannot be exerted on the measurement results according to the present invention.

Next, an embodiment of the concentration control device according to the present invention will be described with reference to FIGS. 6 to 8.

FIG. 6 is a diagram showing the configuration of the concentration control device.

In the figure, the titration device (20G) is shown in the eighth factor, and the water tank (to) is connected to tap water through a water pressure regulating valve (110) and a valve (111). Processing tank (1
The concentration control target (for example, phosphate coating treatment liquid, etc.) in
)→Sample return pump (115) - Processing tank (119) The sample tank (to) is constantly supplied with new samples. An air pump (114) is also connected to the three-way valve (11B). This pump (1
14) is for preventing clogging of the intake port (150). The chemical liquid injection pump (116) is connected to the chemical liquid tank (11
The chemical solution in B) is sent to the processing tank (119).

FIG. 7 is a diagram showing the configuration of an electronic circuit within the titration apparatus (200). The basic configuration is the same as in Fig. 4, but the output port is equipped with each pump (112, 112,
115, 116) are connected, and each pump is controlled by the CPU.

The program written in the ROM of the microcomputer will be explained according to the flowchart of FIG. At a predetermined time (for example, every 80 minutes), the pump (112) is operated to send the sample to the sample tank (step 181).
Print the time and concentration of the 181-182elB sample (steps 184 and 185).

Here, the details of step 184 are the same as the flowchart shown in FIG. Next, the target concentration NE and the measured concentration NX are compared, and if the concentration is insufficient, a chemical solution is injected based on the concentration difference (steps 186 and 187). Thereafter, the system waits until the measurement time of the fire, and when the measurement time arrives, repeats the above operation (step 181).Like Jin, according to this embodiment, the concentration is adjusted at predetermined intervals and the concentration is recorded. I can go.

In this embodiment, no treatment is performed in case of overconcentration, but in other embodiments, it is also possible to inject another chemical solution to lower the concentration.

〔Effect of the invention〕

This invention has the following effects because it uses a switching valve and the nine sample titrants are delivered by the same pump.

(f) Since the same pump is used, the volume ratio of the titrant and sample can be calculated based on the rotational speed of the pump, etc., without having to measure the volumes of the titrant and sample. Therefore, volumetric analysis can be performed with high accuracy without using a high-precision pump that can accurately determine the amount of pumping.

(b) In addition, in conventional methods and devices, even if a high-precision pump is used, the amount of pumping changes due to deterioration of the pump and deterioration of the tube over repeated use, so adjustments are necessary. . However, according to the present invention, since the same pump is used and calculations are made based on the ratio of both liquids, such adjustment is not necessary even if there is a change in the delivery amount.

(c) That is, according to the present invention, highly accurate volumetric analysis can be performed even when a simple squeezing type pump is used.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional titration device, Fig. 2 is an overall configuration diagram to clarify the configuration of the present invention, Fig. 8 is a diagram showing a volumetric analyzer as an embodiment of the present invention, and Fig. 4 8 is a block diagram showing the configuration of the electronic circuit of the capacitance analyzer shown in FIG. 8, FIG. 5 is a flowchart of the program written in the ROM of the electronic circuit shown in FIG. 7 is a block diagram showing the configuration of the electronic circuit of the concentration control device shown in FIG. 6, and FIG. 8 is a block diagram showing the configuration of the electronic circuit shown in FIG. 7. It is a flowchart of the program. (9)...sensor, 9...straining type pump, (
e)...Three-way valve, (B), &4...Three-way valve, (E)...Reaction tank, (
c)...Flow path, member...discharge tank. In the drawings, the same or corresponding parts are given the same reference numerals. Agent Patent Attorney Takaharu Higashijima Figure 1 Figure 2 Riberuuu Senjo no tL Ura Sadaru Night -

Claims (5)

[Claims] (1) A sample delivery step in which a switching valve passes the sample into the enclosure, and a pump provided in the channel sends a predetermined amount of the sample to a reaction tank; and the switching valve passes a cleaning solution into the channel. At the same time, a cleaning step of directing the tip of the flow path to the outside of the reaction tank and discharging the cleaning liquid to the outside of the reaction tank to clean the flow path; and directing the titrant liquid to the flow path using the switching valve. , a titrant delivery step in which the titrant is fed to the reaction tank by the pump until the reaction between the sample and the titrant reaches an end point; a predetermined amount of the sample sent in the sample delivery step; and a titrant delivery step. A volumetric analysis method in which volumetric analysis is performed based on the ratio of the amount of the titrant solution sent in each step. (2) a predetermined claw for the sample in the sample sending step;
The ratio of the amount of the titrant in the titrant delivery stage is calculated based on the ratio of the rotation speed or operating time of the pump in the sample delivery stage and the titrant delivery stage. A volumetric analysis method according to claim 1. (3) a reaction tank, a channel, a valve means for communicating any one of the sample and the nine titration liquids to the channel, a pump provided in the channel, and a pump provided at the tip of the channel. a nozzle, a nozzle switching means for switching whether the nozzle is directed into or out of the reaction tank, a sensor provided in the reaction tank, and a sensor that controls the reaction based on the output of the sensor. end point signal generating means for detecting an end point; counting means for measuring the operation of the pump; quantitative signal generating means for detecting a predetermined amount based on the output of the counting means; and switching of the valve based on the quantitative signal. a valve control signal generating means for controlling the operation of the pump based on the end point signal and the quantitative signal; and a pump control signal generating means for controlling the operation of the pump based on the end point signal and the quantitative signal; filling detection signal generating means for detecting; nozzle control signal generating means for controlling the position of the nozzle based on the quantitative signal and the filling detection signal; and calculating based on the end point signal and the output of the counting means. A capacity analyzer characterized by comprising: a calculation means; (4) The volumetric analyzer according to claim 8, wherein the reaction tank has a discharge tank. (5) The volumetric analyzer according to claim 4, wherein the reaction tank is cylindrical, and the discharge tank is arranged concentrically on the outside of the reaction tank.