JPS63173962A - Wet acid type total organic carbon measuring method and apparatus - Google Patents

Abstract

PURPOSE:To dispense with the measurement and correction of a blank value, by heating an oxidation agent acid solution to remove total carbon components contained in the solution through the conversion thereof into CO2. CONSTITUTION:A fixed amount of an oxidation agent solution and an acid solution are sent to an aeration tank 37 from an oxidation solution tank 30 and from an acid solution tank 31. The solution is heated with a heating furnace 38 and total carbon in the solution is converted into CO2. Then, a carrier gas is sent to the aeration tank 37 from a carrier gas supply section to remove CO2. Thereafter, the solution is transferred to a reaction tank 40 and a fixed amount of a sample is injected from a microsyringe 41. After heating with the heating furnace 42, a valve 22 is opened to introduce the carrier gas and CO2 generated is sent via a water separator 45 and a dehumidifier 46 to a CO2 detector 48. This reduces the total carbon contained in the oxidation agent acid solution to a small level, thereby eliminating the need for operations of measuring and correcting blank values with a smaller blank value due to the oxidation agent and acid.

Description

DETAILED DESCRIPTION OF THE INVENTION A) Ultra-easy Utilization Features This invention is a complete wet wave treatment method for aqueous samples containing organic carbon components (OC) but not inorganic RJArA components (I<:). This paper relates to a method for measuring organic carbon dioxide ('roe) and improvements to the body.

(b) Conventional techniques and problems The wet oxidation TOO measurement method for aqueous samples containing OC involves using an acidic solution of an oxidizing agent such as potassium peroxosulfate or a combination of ultraviolet rays to act on the sample. O
A method is being used in which the C component is converted into carbon dioxide (002) and then measured.

FIG. 1 is an explanatory diagram of the configuration of a conventionally used wet oxidation TOO measuring device, which is operated as follows.

a. A certain amount of OC-containing sample is introduced into the reaction tank 4 through the sample injection port 6 using the microsyringe 7.

b. a certain amount of oxidizing agent (e.g. potassium peroxosulfate);
and a certain amount of an aqueous solution of an acid (for example, phosphoric acid) are injected from the oxidizer solution tank 8 and the acid solution tank 9 into the reaction tank 4 through the conduits 12 and 18 by metering pumps 10 and 11, respectively.

After heating the C1 reaction tank 4 with the heating furnace 6 at a temperature and time sufficient to convert the 00 component in the sample into CO2,
Next, the valve 2 of the carrier gas gas supply unit 1 is opened to allow a constant flow of carrier gas to flow through the pipe 8, and the sample in the reaction tank 4 is passed through the oxidizing agent and the acid, and the OC component derived from the OC component is 002 is passed through a water separator 14 and a dehumidifier 15 using a carrier gas to remove water and humidity, and then sent to a CO2 detector 17 to detect CO2.

d. Calibrate in advance with a standard solution with a known TOOWJ degree, and the data processor 18 calculates f'001 degree in the sample and prints it on a printer or the like.

When measuring TOC using the conventional method described above, simply mix the oxidizing agent and the sample and then heat to oxidize the TOC component.
02, the total carbon content of the oxidizing agent, acid, and water used to prepare them with appropriate precision (a large blank value due to TC is added to the measured value of TOO in the sample). In order to reduce this blank value, it is necessary to use a highly pure oxidizing agent, acid powder, and water, and even if such highly purified oxidizing agents are used, there is a risk of contamination from the outside during the preparation of the oxidizing agent solution. A non-negligible amount of To is detected.Therefore, conventionally, correction is performed by performing a similar measurement operation without injecting a sample to obtain a blank value in advance and subtracting it.

However, for example, 5% potassium peroxosulfate 2I11/
, 0.6 d of 10% phosphoric acid, the blank value attributable to To contained in these oxidizing agents is about 8 μf, and the standard deviation when measured five times is 0.07 μf. When measuring a sample, variations in this blank value are always added, and this becomes a major cause of deterioration of sample measurement accuracy. For example, 10 m) 1) When a standard solution of mTOC is measured 5 times using this method, the relative standard deviation (C, V, ) is 1
．． It became 04%.

This effect is particularly large when measuring a trace amount of To(3).

(c) Means for solving the problems This invention was made to improve the above problems.
As a first invention, an oxidizing agent or a combination of the same and ultraviolet rays are applied to an aqueous sample containing an organic carbon component but not a carbon free component to convert the organic carbon component in the sample into carbon dioxide. In the method of measuring total organic carbon by exhausting carbon dioxide with a carrier gas and quantifying it, an acidic oxidizing agent solution is sufficiently heated in advance to convert the organic carbon component contained in this solution into carbon dioxide, and this is converted into a carrier gas. After removal by gas, the sample is mixed and sufficiently heated to convert the organic carbon components in the sample into carbon dioxide, and this carbon dioxide is discharged with a carrier gas and quantified to measure total organic carbon. This provides a wet oxidation total organic carbon measurement method.

The sample in this invention is an aqueous sample that does not contain IC but contains OC, but if the sample contains both IC and OC components, the IC component is removed in advance and the sample is used as a measurement sample. . The IC component is easily converted to 002 by adjusting the pH of the sample to 2 to 4, and this CO2 can be easily removed by IFc with nitrogen gas that does not substantially contain 0027. Note that the amount of sample is generally in the range of 10 μg to 10#/, and is small for high-concentration TOO samples (large amount is used for low-concentration TOO samples).

The oxidizing agent used in this invention may be any conventionally used oxidizing agent, such as potassium peroxosulfate. Furthermore, the acid for making the aqueous solution of the oxidizing agent acidic may be any conventionally used acid, including inorganic acids such as phosphoric acid and sulfuric acid.

Oxidizing agents and acids are generally used as aqueous solutions, but when using potassium peroxosulfate as the oxidizing agent,
A 0 to 10% aqueous solution is used, and a 5 to 15% aqueous solution is used when, for example, phosphoric acid is used as the acid.

In this invention, first, an acidic oxidizing agent solution, which is a mixed aqueous solution of an oxidizing agent and an acid, is heated to convert all the carbon (To) into OOg and remove it. The heating is about 90-100℃
Approximately 3 to 6 minutes is sufficient. Generally, when an oxidizing agent is heated, its oxidizing power gradually decreases, but this level of heating does not pose a practical problem.

The OOg generated by heating is removed by aerating the solution through a carrier gas such as nitrogen gas, oxygen gas, purified air, etc. that does not substantially contain CO2, and discharging the solution together with the carrier gas. This carrier gas is generally 50%
It is used at about 150g//m.

Next, the sample is mixed with the oxidizing agent acidic solution treated in this way to remove To, heated as described above to convert the OC to CO2, and discharged together with the carrier gas in the same manner as described above. TOC of the sample is calculated by detecting CO2 with a CO2 detector.

Next, this invention provides, as a second invention, a measuring device for carrying out the above-mentioned @1 invention, an aeration tank equipped with a heating furnace and an exhaust port, and an aeration tank equipped with a heating furnace and a sample injection port. A reaction tank, a water separator, a dehumidifier, and a data processor are attached, and a carbon dioxide detector with an exhaust line on the outlet side is connected by a pipe, and a pump for sending liquid extends from the oxidizer solution tank. A liquid sending pipe and a liquid sending pipe with a liquid sending pump extending from the acid solution tank are connected to the aeration tank, and one of the two valved pipes extending from the carrier gas supply section is connected to the l air water,
The other is connected to the reaction tank, and first, the oxidizing agent acidic solution is heated in the aeration tank and aerated with a carrier gas to convert all the carbon components into carbon dioxide and remove it, and this solution and the inorganic carbon component are A wet oxidation type all-organic system that is configured to mix a sample that does not contain carbon dioxide with a sample that contains an organic carbon component, heat it, convert the organic carbon component to carbon dioxide, detect this, and calculate the amount of organic carbon. The present invention provides a carbon measuring device.

First, the oxidizing agent and the oxidizing agent acidic solution sent from the acid solution delivery pipeline are injected into the aeration tank, and heated in a heating furnace attached around the tank to convert To in the solution into CO2, and the carrier gas A carrier gas sent from the supply unit to the aeration tank is passed through the solution, aerated, and discharged to the outside from the exhaust port of the aeration tank to remove CO2.

The solution from which To has been removed in this way is sent to a reaction tank, and then a sample is added thereto. Next, this is heated in a heating furnace attached to the reaction tank to convert the OC in the sample into CO2, and this CO2 is separated by a carrier gas sent to the reaction tank, and then passed through a water separator and dehumidifier to remove moisture. After removing moisture, it is sent to a CO2 detector where it is detected and measured, and a data processor calculates and prints out the TOC amount.

The aeration tank and reaction tank are usually made of hard glass or quartz glass. Conventionally used water separators and dehumidifiers are used, and a non-separating infrared analyzer (usually measured by peak area) is used as the CO2 detector. The sample, reagent, heating conditions, carrier gas, etc. are the same as described above.

Next, the present invention will be explained by examples, but the present invention is not limited thereto.

B) Example First, a case in which measurement is carried out by the method of the present invention using the apparatus shown in FIG. 1 will be explained step by step.

a1. A metering pump 10 supplies a certain amount of oxidizing agent solution and a certain amount of acid solution from an oxidizing agent solution tank 8 and an acid solution 9, respectively.
and 11 into the reaction tank 4.

b1. The heating furnace 6 is heated to a temperature of about 90℃
The temperature is maintained at 95° C. for about 3 to 4 minutes to convert the TO in the oxidizing agent acidic solution to carbon dioxide, and then the temperature increase is stopped.

The valve 2 is opened and the carrier gas is sent from the carrier gas supply section 1 to the reaction tank 4 through the pipe line 8, and the generated C02
is discharged to the outside by carrier gas. Next, the supply of the carrier gas is stopped and the temperature of the reaction tank 4 is lowered to room temperature.

c1. A certain amount of sample is injected into the reaction tank 4 through the sample injection port 6 using the microsyringe 7 .

d1. By raising the temperature of the heating furnace 6, the temperature of the reaction tank 4 is about 90~90℃.
After holding the sample at 5°C for about 3 to 4 minutes to convert TOO in the sample into carbon dioxide, the sample is aerated with a carrier gas and passed through a water separator 1114 and a dehumidifier 16 to remove water and moisture. The gas is then sent to the non-separating infrared gas analyzer 17 of the C02 detector to detect C02.

e l. The TOOa degree in the sample is calculated by the data processor 18 by calibrating and windowing with a standard solution whose TOOd degree is known in advance and printed on a printer or the like.

Note that if there is no volatile (low boiling point) OC component in the sample, the procedure may proceed to step 01 without stopping the carrier gas and lowering the temperature of the reaction tank to room temperature in step b1.

Next, an embodiment of the measuring device of the present invention shown in FIG. 2 will be described.

a2. Add a certain amount of oxidizing agent aqueous solution and acid aqueous solution＼(
fl) used for one analysis of the sample, oxidizing agent solution tank 8
0 and acid solution tank 81 by means of metering pumps 82 and 88 (which may be suitable dispensers) through lines 84 and 35 to aeration tank 37 (valves 25 and 26 closed).

b2. The temperature of the heating furnace 38 is increased to bring the solution to about 95%
Heat at ℃ for about 4 minutes. As a result, To in the solution is C
Converted to O2. Then, the valve 26 is opened to send the carrier gas from the carrier gas supply section 21 through the pipe 24 to the aeration 137, and the solution is passed through and aerated and discharged from the exhaust port 39 to remove the CO.

C2, open the valve 26 and allow the entire amount of the heated and aerated solution to flow down into the reaction tank 40.

d2. The valve 26 is closed, and a certain sample is taken with the microsyringe 41 and injected into the reaction tank 40 from the sample injection port (an appropriate automatic sample injector may be used for this operation).

e2. The temperature of the heating unit 42 is raised to heat the mixed liquid 48 at 95° C. for about 4 minutes. As a result, the OC in the sample was (
Next, the valve 22 is opened and the carrier gas is supplied from the carrier gas supply section 21 through the pipe line 28 at a constant flow rate to the mixed liquid 4B of the sample and the solution.
Pass aeration inside. The generated CO2 passes through a water separator 45 and a dehumidifier 46 together with the carrier gas to remove water and humidity, and is sent to a CO2 detector 48 where CO2 is detected, and a data processor 49 calculates and prints OaZ. Although not shown in Figure 2, CO2 detection 'a48
A CO2 trap section may be installed in front of the reactor, and after the CO2 sent from the reaction tank is once trapped by this trap, the trap section may be heated to release CO2 for measurement. The same thing can be said about the device shown in FIG.

In the embodiments described above, the amount of To component in the oxidizing agent acidic solution is zero or a very small value close to zero, so that the measurement accuracy is improved. For example, when a standard solution of ioppmTOC similar to the conventional example was tested using the apparatus shown in FIG. 1 and the method of the present invention, the relative standard deviation was 0.61%.

(e) Effects of the invention According to this invention, the following excellent effects can be obtained.

(1) Measurement accuracy is improved because the blank value due to oxidizing agent or acid becomes zero.

(II) TC in the oxidizing agent, acid salt, and water used for its preparation.
Even if an ingredient is included as an impurity, it has no effect. Further, there is no need to consider contamination during preparation operations.

n++) Blank value measurement and correction operations are not required.

GV) Even if the accuracy of the injection amount of the oxidizing agent and acid solution is somewhat poor, it does not directly affect the measurement (for example, an error of about 10% does not affect it).

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a conventional wet oxidation type total sterile carbon measuring device, and FIG. 2 is a configuration explanatory diagram of a wet oxidation type total 1 carbon measuring device according to an embodiment of the present invention. be. (1,21)...Carrier supply section, (8,80)...
・Oxidizer solution tank, (9,81)...Acid solution tank, (7゜41)...Microsyringe, (4,40)...Reaction 1, (6,44)...Sample injection Entrance, (14,45)
...Water separator, (15,46) ...Dehumidifier, (17
゜48)...CO2 detector, (18,49)...
・Data processor.

Claims (1)

[Claims] 1. An oxidizing agent or a combination of the same and ultraviolet rays is applied to an aqueous sample containing an organic carbon component but not an inorganic carbon component to convert the organic carbon component in the sample into carbon dioxide. However, in the method of measuring total organic carbon by exhausting this carbon dioxide with a carrier gas and quantifying it, the oxidizing agent acidic solution is sufficiently heated in advance to convert the organic carbon component contained in this solution into carbon dioxide. After removing this with a carrier gas, the sample is mixed and heated sufficiently to convert the organic carbon component in the sample into carbon dioxide, and this carbon dioxide is exhausted with a carrier gas and quantified to measure total organic carbon. A wet oxidation total organic carbon measurement method characterized by: 2. Aeration tank with heating furnace and exhaust port, reaction tank with heating furnace and sample injection port, water separator, dehumidifier,
A carbon dioxide detector with a data processor attached and an exhaust pipe on the outlet side is connected by a pipe, and a liquid sending pipe with a liquid sending pump extending from the oxidizing agent solution tank and the acid solution tank. A liquid feeding pipe line with an extending liquid feeding pump is connected to the aeration tank, one of the two valved pipe lines extending from the carrier gas supply section is connected to the aeration tank, and the other is connected to the reaction tank. First, the oxidizer acidic solution is heated in an aeration tank and aerated with a carrier gas to convert all the carbon components into carbon dioxide and remove them.
This solution is mixed with a sample containing an organic carbon component but not an inorganic carbon component, and heated to convert the organic carbon component into carbon dioxide, which is detected to calculate the amount of organic carbon. A wet oxidation total organic carbon measuring device.