JP3323049B2 - Water quality analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water quality analyzer for analyzing water quality using high performance liquid chromatography in a water quality test for easily grasping the treatment status of each treatment step of a water treatment facility represented by a water supply facility. In particular, the present invention relates to a water quality analyzer capable of simultaneously analyzing the whole dissolved substance and dissolved organic matter at the same time.

[0002]

2. Description of the Related Art In the field of water treatment, various characteristics such as raw water for tap water such as rivers, lakes and mars, groundwater, various kinds of water for environmental use, drainage, treated water in each treatment step of water supply facilities, discharged water and drinking water, and bottled water. There is water with In these water treatment facilities, organic matter removal is one of the important treatments, and there are a wide variety of organic matter items and measurement methods that can be removed by physicochemical and biological treatment methods. Organic matter is roughly divided into floating organic matter and dissolved organic matter, and its abundance is measured from the measurement of the total amount of floating organic matter and dissolved organic matter to the measurement of the low-concentration trace amount of dissolved organic matter. Understanding is important and essential for the evaluation of water treatment facilities.

[0003] As a representative index of the amount of organic matter, measurement of COD, BOD, and TOC is generally considered. However, when a trace amount of dissolved organic matter of several tens of ppb is targeted, the measurement limit of these methods is exceeded. Accuracy is required. In addition, although these methods are automated, there are many complicated devices and a large amount of sample is required. Furthermore, in the measurement of low-concentration trace dissolved organic substances by a TOC measuring device or gas chromatograph mass spectrometry, pretreatment such as concentration at a laboratory level or extraction of a solvent is required, and there is a problem in reproducibility and measurement accuracy.

Therefore, a water quality analyzer using high performance liquid chromatography, which can measure dissolved substances in a relatively short time, has begun to be used in recent years. This water quality analyzer is composed of a liquid chromatography section consisting of a column and a developing solvent for fractionating a sample according to molecular weight, and a detection section consisting of a conductivity detector, a refractive index detector, an ultraviolet absorption detector, and a fluorescence detector. In particular, salts and buffer solutions are used as developing solvents to maintain the characteristics of gel filtration packed columns.

[0005] In such a water quality analyzer, even when the electric conductivity or the refractive index, which is an index of the entire dissolved substance, is detected, the concentration of the dissolved inorganic substance in the developing solvent is higher than the concentration of the dissolved substance in the sample. Measurement cannot be performed.

On the other hand, when a salt or a buffer solution is used as a developing solvent, it is possible to measure only dissolved organic substances. For example, the absorption intensity at a specific wavelength can be measured using an ultraviolet absorption detector, and can be used as an index of a dissolved organic substance. This method is an example of an effective analysis method that can predict the abundance of a typical dissolved organic substance having an unsaturated bond in the molecular structure, and can measure the ppb level. However, since this analysis method responds only to a substance having an ultraviolet absorption property, it cannot show the entire dissolved organic matter.

FIG. 9 shows an example of a water quality analyzer using such high performance liquid chromatography. As shown in FIG. 9, the mobile phase salt and buffer solution in the tank 1 are sent to the sample injector 4 by the liquid sending pump 3, and together with the sample injected by the syringe 5, together with the aqueous gel filtration packed column 6. Where the molecular weight fractionation occurs. The fractionated dissolved substances are sent to the ultraviolet absorption detector 10 in order of decreasing molecular weight, where specific dissolved organic substances are detected, and a chromatogram is recorded in the recorder 9.

[0008]

Regarding the dissolved substances in each step of the water treatment facility, dissolved organic matter accounts for the majority in sewage and wastewater treatment, and dissolved inorganic matter accounts for the majority in tap water and industrial water. In evaluating such treated water in water and sewage facilities, it is necessary to grasp the overall characteristics of dissolved substances including inorganic substances as well as dissolved organic substances. In this case, when a salt or a buffer solution is used as a developing solvent, both detection of a dissolved organic substance such as ultraviolet absorption and fluorescence and detection of the entire dissolved substance such as electric conductivity and refractive index cannot be performed simultaneously. Further, depending on the pH, the salt and the developing solvent of the buffer solution affect dissolved substances in the sample, and it is difficult to perform highly accurate measurement.

The present invention has been made in consideration of the above points, and simultaneously and simultaneously enhances the characteristics of the dissolved substance as a whole, including inorganic and organic substances, and the characteristics of the dissolved organic substance, which is a main operating factor in water treatment. It is an object of the present invention to provide a water quality analyzer capable of detecting with high sensitivity.

[0010]

SUMMARY OF THE INVENTION The present invention provides an aqueous gel filtration packed column for separating substances in order of molecular weight,
A developing solvent supply device for transferring the developing solvent to the aqueous gel filtration packed column side, a sample injection device for injecting a sample into the developing solvent transferred from the developing solvent supply device to the aqueous gel filtration packed column side, and the aqueous gel An inert gas injection device for injecting an inert gas into the developing solvent transferred to the filtration packed column side, using pure water as the developing solvent, and having a solubility on the downstream side of the aqueous gel filtration packed column. A water quality analyzer comprising a detector for organic substances and a detector for all dissolved substances arranged in series.

[0011] While transferring pure water as a developing solvent from the developing solvent supply device to the aqueous gel filtration packed column side,
A sample is injected into the developing solvent from a sample injection device. The sample is separated in a water-based gel filtration packed column in the order of molecular weight, and the separated substances are detected by a detector for dissolved organic substances and a detector for all dissolved substances. Further, by injecting the inert gas into the developing solvent, the use time until the regeneration of the column packed with the aqueous gel filtration can be extended.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment An embodiment of the present invention will be described below with reference to the drawings. 1 to 8 show a first embodiment of the water quality analyzer according to the present invention.

In FIG. 1, a water quality analyzer includes a first solution storing, for example, a 0.1 M Na ₂ SO ₄ solution (regenerating solution).
A storage tank 1A and a second storage tank 2 for storing pure water (developing solvent) are provided. The first storage tank 1A and the second storage tank 2 are arranged in parallel with each other and connected to the liquid feed pump 3 respectively. Have been. The second storage tank 2 for storing pure water includes:
An inert gas injector 2A for injecting an inert gas, for example, a nitrogen gas, into the second storage tank 2 is connected.

The liquid sending pump 3 further includes a sample injector 4, a water-based gel filtration packed column 6 having a filter material as a base material and separating substances in order of molecular weight, and a differential refractive index for detecting the entire dissolved substance. A total 7, and a fluorometer 8 for detecting dissolved organic matter are directly connected in sequence.

A recorder 9 for creating a chromatogram is connected to the differential refractometer 7 and the fluorometer 8. The differential refractometer 7 and the fluorometer 8 may be exchanged, and the fluorometer 8 and the differential refractometer 7 may be arranged in this order on the downstream side of the aqueous gel filtration packed column 6.

The sample injector 4 has a sample inlet 4A and a switching valve 4 for switching between sample injection and developing solvent.
B and a sample loop container 4C in which the amount of the dissolved substance of the sample is considered in advance. The capacity of the sample loop container 4C is determined in proportion to the amount of the dissolved substance. For example, 500 μl for water purification and 500 μl for sewage. 20 μl is used. Further, a syringe 5 having a 0.45 μm filter is connected to the sample injection port 4A, and an excess sample injected from the syringe 5 is discharged out of the system as an excess sample waste liquid from the sample loop container 4c. In addition, the sample injector 4
The syringe 5 constitutes a sample injection device.

Next, the operation of this embodiment having the above configuration will be described.

First, pretreatment (regeneration) of the column is performed to stabilize the water quality analyzer. In the first storage tank 1A, a Na ₂ SO ₄ solution as a regenerating solution is ultrasonically degassed for 30 minutes or more under reduced pressure, and then the solution is supplied to the solution sending pump 3 at a flow rate of 0.5 ml /
The sample flows through the sample injector 4 and the column 6 filled with aqueous gel filtration for at least 4 hours at a minimum. Next, the second
Pure water degassed in the same manner in the storage tank 2 flows through the sample injector 4 and the column 6 packed with aqueous gel filtration at a flow rate of 0.5 ml / min for 3 hours by the liquid sending pump 3. Flow for 1 hour at 0 ml / min.
Thus, the regeneration of the column 6 is performed. The second
In the storage tank 2, nitrogen gas is injected into the pure water from the inert gas injection device 2 at the same time as ultrasonic degassing, and carbon dioxide in the pure water is discharged. By discharging carbon dioxide in pure water in this way, the column packed with hydrogen gel filtration 6
Is prevented from being reduced.

Next, if necessary, the column separation ability is confirmed with the standard sample and the sensitivity of the detector is corrected. For example, an aqueous solution containing polyethylene glycol or pyrenesulfonic acid having different average molecular weights is injected from the syringe 5 into the sample injector 4, and the sensitivity of the differential refractometer 7 and the fluorometer 8 is corrected.

Here, another organic substance may be used as the standard substance.

Next, the sample is measured. First, a sample is injected from the syringe 5 into the sample injector 4 from the sample injection port 4A. The sample is stored in the sample loop container 4C from the sample inlet 4A, and the excess sample is discharged out of the system as excess sample waste liquid. Next, when the switching valve 4B is switched,
A required amount of the sample retained in the sample loop container 4C is transferred to the aqueous gel filtration packed column 6 based on an aqueous gel filtration material together with pure water as a developing solvent sent by the liquid sending pump 3. It is fractionated in order from a substance having a large molecular weight.

The dissolved substance fractionated from the high molecular to the low molecular due to the difference in the outflow time is detected by the differential refractometer 7 and the fluorometer 8 and the chromatogram is simultaneously prepared by the recorder 9.

As the aqueous gel filtration packed column 6, a packed column generally made of a hydrophilic silica gel or the like having a three-dimensional network structure is used. However, since the surface of the column base material is hydrophilic, has hydroxyl groups and has some ion exchange ability, when pure water is used as a developing solvent, the resolution decreases with time due to interaction with ions.

The inventor of the present invention has shown in many experimental examples that when pure water is used as a developing solvent for about 2 hours or more, the resolution of the aqueous gel filtration packed column 6 is greatly reduced, and pure water is inert gas such as nitrogen gas. It was confirmed that the use time of the water-based gel filtration packed column 6 was approximately tripled when the column was purged and the carbon dioxide was released as much as possible. In addition, the measurement can be performed again by performing the regeneration operation of the column 6 packed with the aqueous gel filtration.

By repeating such a reproducing operation, intermittent measurement of the sample becomes possible. By utilizing such characteristics of the aqueous gel filtration packed column and by sequentially measuring a plurality of the aqueous gel filtration packed columns 6 in combination,
Continuous measurement is also possible.

Here, in order to clarify the features of the present invention,
The water quality analyzer according to the present invention will be described with reference to an example of analysis of tap water using surface water of a river that has been contaminated with organic substances as raw water.

First, as a comparative example, using a water quality analyzer shown in FIG. 1 without the inert gas injection device 2A, tap water (sample) of a large city was injected without injecting inert gas into pure water. When analyzed, a chromatogram of refractive index and fluorescence is obtained as shown in FIG. When a similar sample is continuously analyzed several times, the resolution of the aqueous gel filtration packed column 6 gradually decreases, and the regeneration of the aqueous gel filtration packed column 6 is required.

Next, in order to examine the influence of the gas dissolved in the sample in the comparative example, the sample was aerated with nitrogen, oxygen and carbon dioxide, and the chromatograms of FIGS. 3, 4 and 5 were obtained. It was found that carbon dioxide dissolved in the sample had a greater effect on the separation characteristics of the aqueous gel filtration column 6 than nitrogen or oxygen dissolved in the sample. Furthermore, in order to examine the stability of the aqueous gel filtration packed column 6 in the comparative example, the samples aerated with each gas were continuously injected into the aqueous gel filtration packed column 6. As shown in FIG. 6, it was found that the outflow time was delayed, and the resolution of the column 6 packed with the aqueous gel filtration was reduced at a stroke. Therefore, the present inventors have come to the present invention in view of the fact that carbon dioxide has a significant effect when using pure water as a developing solvent in the aqueous gel filtration packed column 6.

That is, when pure water is used as a developing solvent in the present invention shown in FIG.
Inject nitrogen gas into pure water in the second storage tank 2 by A,
By aeration of the pure water, the life of the column 6 packed with water-based gel filtration can be maintained long. As an inert gas, it goes without saying that oxygen, helium, etc. which do not affect the column 6 packed with the aqueous gel filtration can be used other than nitrogen. Further, pure water in the second storage tank 2, which is a developing solvent, may be aerated with an inert gas, and then sealed and used with a similar inert gas.

FIG. 7 shows a comparison between the present invention and a comparative example in which pure water is not aerated with an inert gas. When the change is compared with the time difference between the first peak and the fourth peak of the chromatogram,
In the comparative example, the appearance of the first peak is delayed by analysis of the sample for 4 to 5 times. That is, in the comparative example, the resolution of the column 6 packed with the aqueous gel filtration is reduced by the analysis of 4 to 5 times and regeneration is required.
In the case of the present invention in which the sample was aerated with nitrogen by A, even if 17 samples were analyzed, the difference between the peaks did not change much, indicating that stable analysis with good reproducibility was possible.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. In the second embodiment shown in FIG. 8, the same parts as those in the first embodiment shown in FIGS. 1 to 7 are denoted by the same reference numerals, and detailed description is omitted. In FIG. 8, a first storage tank 1A for storing the regenerating liquid and a second storage tank 2 for storing the pure water are arranged in parallel, and the liquid feed pumps 3A, 3A are respectively provided.
B allows the regenerating solution and pure water to be sent to the sample injector 4 side. In addition, liquid sending pumps 3A and 3B
Is connected to the inlet valve 3E on the upstream side of the sample injector 4.

The second storage tank 2 is connected to a pipeline from the first storage tank 1A to the liquid feed pump 3A via a switching valve 3D, and further connected to a flow control device 3C to the liquid feed pump 3A. I have. An inert gas injection device 2A is connected to the second storage tank 2.

An outlet valve 6A is connected to the downstream side of the aqueous gel filtration packed column 6, and this outlet valve 6A sends liquid in the system to either the differential refractometer 7 or outside the system. I have.

In FIG. 8, pure water as a developing solvent, which has been sufficiently purged by injecting nitrogen gas with the inert gas injector 2A, reaches the column 6 filled with aqueous gel filtration by the liquid sending pump 3A for measurement for 6 hours. Is done.

In six hours after the start of the measurement, the message that measurement is impossible is displayed, the switching valve 3D is switched from the pure water side to the Na ₂ SO ₄ side, and at the same time, the inlet valve 3E and the outlet valve 6A are switched to the regeneration side.

Next, Na ₂ SO ₄ is flowed at a flow rate of 0.5 ml / min for 4 hours or more by a liquid feed pump 3B having a flow rate adjusting device 3C, and then the switching valve 3D is switched to the pure water side, and the flow rate is reduced to 0. Pure water is flown at 5 ml / min for 2 hours through the sample injector 4 and the column 6 packed with aqueous gel filtration, and further purified water is flowed at 1.0 ml / min for 1 hour, thereby completing regeneration of the column 6 packed with aqueous gel filtration. Is displayed. Note that a display device and a control device for the measurable time, the reproduction end time, and the like are separately provided.
As a result, the packed column can be used under optimal conditions.

If the time required for regeneration is 8 hours, the measurable time is 6 hours. Therefore, continuous measurement can be performed for 24 hours with three sets of the aqueous gel filtration packed columns 6.

In addition to the automatic reproduction method using such a timer, the following method is also available. That is, the standard sample is flowed immediately after the regeneration, and the peak shape and the retention time of the chromatogram are stored in a storage device (not shown). After flowing the measurement sample for 6 hours, the standard sample is flown according to a timer command and compared with the data stored in the storage device. If a difference between the peak holding time and a certain set value is found, the process proceeds to the regeneration step. If no difference exceeding the set value is observed, the measurement is continued, and after measuring several samples, the standard sample is flown again and compared with the stored data. By the same operation, the measurement can be continued to the maximum extent within a range where the separation characteristics of the column do not deteriorate. Needless to say, these series of operations can be automatically performed, and the set values of the timer and the like can be changed.

[0039]

As described above, according to the present invention, the characteristics of the dissolved organic matter and the entire dissolved substance can be simultaneously detected, and the operation management of the water treatment facility can be efficiently performed. Further, by injecting the inert gas into the developing solvent, the use time until regeneration of the column packed with the aqueous gel filtration can be extended, and the efficiency of operation management can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a water analyzer according to the present invention.

FIG. 2 is a diagram showing a chromatogram of refractive index and fluorescence of city water.

FIG. 3 is a diagram showing a chromatogram of refractive index and fluorescence of tap water aerated with nitrogen gas.

FIG. 4 is a diagram showing a chromatogram of refractive index and fluorescence of tap water aerated with oxygen gas.

FIG. 5 is a diagram showing a chromatogram of refractive index and fluorescence of tap water aerated with carbon dioxide gas.

FIG. 6 is a diagram showing a chromatogram of refractive index and fluorescence of tap water when a column packed with aqueous gel filtration whose resolution has been reduced by carbon dioxide is used.

FIG. 7 is a diagram comparing the present invention with a comparative example with respect to the reproducibility of the refractive index peak retention time when the same tap water sample is continuously measured.

FIG. 8 is a view showing a second embodiment of the water analyzer according to the present invention.

FIG. 9 is a schematic diagram showing a conventional water analyzer.

[Explanation of symbols]

 Reference Signs List 1A First storage tank 2 Second storage tank 2A Inert gas injection device 3, 3A, 3B Liquid feed pump 3C Flow control device 3D, 4B Switching valve 3E Inlet valve 4 Sample injector 4A Sample injection port 4C Sample loop container 5 Syringe 6 Silica gel packed column 6A Outlet valve 7 Differential refractometer 8 Fluorometer 9 Recorder

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI G01N 33/18 101 G01N 33/18 101 106 106Z (72) Inventor Tadahiro Ishii 1-3-3 Kagurazaka, Shinjuku-ku, Tokyo School corporation Tokyo University of Science (72) Inventor Yoshihiko Tezuka 1-3-3 Kagurazaka, Shinjuku-ku, Tokyo School Corporation Tokyo University of Science (56) References JP-A-8-145977 (JP, A) JP-A-7-128323 (JP, A) JP-A-7-63725 (JP, A) JP-A-1-143953 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 30/88 G01N 30 / 26 G01N 30/78 G01N 33/18

Claims (3)

(57) [Claims] 1. An aqueous gel filtration packed column for separating substances in order of molecular weight, a developing solvent supply device for transferring a developing solvent to the aqueous gel filtration packed column, and an aqueous gel filtration packing from the developing solvent supply device. A sample injection device for injecting a sample into the developing solvent transferred to the column side, and an inert gas injection device for injecting an inert gas into the developing solvent transferred to the aqueous gel filtration packed column side, A water quality analyzer, wherein pure water is used as a developing solvent, and a detector for dissolved organic substances and a detector for all dissolved substances are arranged in series downstream of the column packed with aqueous gel filtration. 2. A regenerating solution supply device for supplying a regenerating solution to the aqueous gel filtration packed column is provided in parallel with the developing solvent supply device on the upstream side of the aqueous gel filtration packed column. Water quality analyzer. 3. An aqueous gel filtration packed column and a developing solvent supply device and a regenerating solution supply device arranged in parallel with each other,
A switching mechanism for selectively transferring the developing solvent or the regenerating solution to the aqueous gel filtration packed column is provided, and a waste liquid discharging device for discharging the waste liquid during regeneration to the outside is provided at the outlet of the aqueous gel filtration packed column. The water quality analyzer according to claim 1, wherein