JPH0579988A - Humic acid quantification using chemical luminescence - Google Patents

Abstract

PURPOSE:To provide humic acid quantification applicable to a continuous analyzing/measuring device provided on a water supply purifying processor by quickly measuring the humic acid concentration in a specimen with high precision. CONSTITUTION:Hydrogen peroxide and formaldehyde are added to a humic acid-containing specimen, alkali such as sodium hydroxide is added to adjust PH for chemical luminescence, and the luminescence intensity in the preset wavelength, preferably the maximum luminescence wavelength, in the luminescence spectrum is extracted and recorded as the electric signal amplified by a photomultiplier and an amplifier. This luminescence intensity is compared with the luminescence intensity/humic acid concentration calibration curve measured separately for quantification. The measured value is precise because it can be measured to the unit of ppb, the humic acid concentration is directly measured, thus the quantification result is quickly obtained continuously.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for quantifying humic acid using chemiluminescence, which is applied to analysis of tap water and other industrial analytical treatments.

[0002]

Humic acid is an acidic organic substance generally existing in soil or calcareous matter with low coalification degree, and its chemical structure is not well known, but its main structure is
It is considered to be a condensation product of a polyhydric phenol type aromatic compound and a nitrogen-containing compound.

The humic acid is also contained in the raw water of the water supply, but when the raw water is sterilized with chlorine, it may be modified into trihalomethane. Trihalomethane is a powerful drug that seriously impairs human or animal functions, and it is necessary to take measures for water purification treatment by knowing the concentration of humic acid, which is a precursor in the raw water before the sterilization treatment.

As a method for quantifying such humic acid, E
Masked with DTA complex salt, visible part of humic acid (410
(-480 nm) was used.

[0005]

However, in the above-mentioned conventional method for quantifying humic acid, pretreatment such as masking takes time, operation of cells and the like is complicated, and measurement results can be obtained continuously. It also had a problem that it could not be done.

The present invention solves the above-mentioned problems in the conventional humic acid determination method, can measure humic acid in a sample with high accuracy and speed, and can perform continuous analytical measurement attached to a water purification system or the like. It is an object to provide a humic acid determination method that can be applied to devices and the like.

[0007]

In order to solve the above problems, in the present invention, hydrogen peroxide and formaldehyde are added to a humic acid-containing sample to cause chemiluminescence, and the luminescence intensity at a predetermined wavelength in the luminescence spectrum thereof. Was converted into an electric signal by a photoelectric tube and measured, and a means for quantifying by comparing the emission intensity and the emission intensity at the predetermined wavelength separately measured with the humic acid concentration calibration curve was adopted.

[0008]

The method for determining humic acid using chemiluminescence according to the present invention finds a phenomenon of chemiluminescence when humic acid, hydrogen peroxide and formaldehyde in a sample are reacted,
Of the emission spectrum, the emission intensity at an appropriate wavelength (preferably the maximum emission wavelength) is measured from the phototube as an electric signal. On the other hand, by comparing and adding the hydrogen peroxide and formaldehyde to a specimen of known humic acid concentration under the same conditions to produce luminescence intensity at the wavelength-contrast the luminescence intensity to a calibration curve of the humic acid concentration, it can be rapidly and accurately measured. The humic acid component of the sample is quantified.

[0009]

EXAMPLE Formaldehyde used in the present invention is HC
Commercially available formalin, which is a 40% aqueous solution of HO, may be used at an appropriate concentration, or paraformaldehyde, polyformaldehyde or the like, which is a derivative of formaldehyde, may be selectively used.

In order to facilitate the decomposition reaction of hydrogen peroxide used in the present invention, the pH in the reaction vessel may be adjusted to about 4 to 5 by adding an alkali such as sodium hydroxide. desirable.

If a metal catalyst is added as a condition for the chemiluminescence reaction other than the above PH, the luminescence intensity increases.
Higher sensitivity measurement is possible.

The following experiment was carried out in order to investigate the wavelength that can be used for measuring the emission intensity in the present invention, that is, the wavelength that can be input to the photoelectric tube.

That is, the amounts and concentrations of formaldehyde and hydrogen peroxide are arbitrarily set, the pH is adjusted, and these are reacted with humic acid efficiently, and the wavelength range is 185 to 85.
Light with a maximum emission wavelength of 640 nm was detected using a photomultiplier tube having a spectral sensitivity of 0 nm.

Next, an experimental example of the quantification device using the wavelength of the maximum emission intensity investigated in the above experiment will be described.

[Experimental Example] First, an emission intensity-humic acid concentration calibration curve was prepared using the apparatus shown in FIG. That is, the humic acid standard concentration liquid 1 having a concentration of 10, 20, 40, and 100 ppm was supplied to the mixing pipe 3 through the peristaltic pump 2 at a flow rate of 2 ml / min, while the 3% hydrogen peroxide solution 4 was supplied. The mixture was introduced into the stirring container 5 at a flow rate of 2 ml / min, and in the stirring container 5, 2 ml / min of a commercially available 5% aqueous solution of formaldehyde 6 and 2 ml / min of a 1 molar sodium hydroxide aqueous solution 7 were further introduced. Was introduced into the stirring container 5 from the peristaltic pump 2 at a flow rate of 1, and the mixed liquid after stirring was further supplied to the mixing tube 3 to be mixed with the humic acid standard concentration liquid 1 and supplied to the reaction container 8. The reaction conditions in the reaction vessel 8 were room temperature and atmospheric pressure.

The reaction vessel 8 is connected to a photomultiplier tube 9 with a spectral filter to detect the intensity of the generated chemiluminescence at the maximum emission wavelength of 640 nm as an electric signal amount, and the emission intensity (relative to the relative intensity via an amplifier 10). Value) Recorder 1
Entered in 1. The emission intensity at each obtained humic acid concentration was plotted on a logarithmic log graph to obtain a linear calibration curve (see FIG. 2).

Next, the concentration of the humic acid-containing specimen A of unknown concentration was determined as follows.

That is, instead of the humic acid standard concentration liquid 1, the humic acid-containing sample A is introduced into the mixing tube 3, and the hydrogen peroxide solution 4, the formaldehyde solution 6, and the sodium hydroxide solution 7 are treated in exactly the same manner as above. Supply to the mixing tube 3,
The humic acid concentration of the sample A was determined by comparing the emission intensity with the recorded detection line. The waste liquid in the reaction container 8 was stored in the waste liquid reservoir 13 by the vacuum pump 12.

The detection limit of humic acid concentration in the above experimental example is 10
ppb, standard deviation of 5 measurements at 1 ppm was 2.3%.

If the shape of the reaction vessel 8 is changed, the coating and the reaction cell are installed, it is possible to obtain the measurement sensitivity and reliability above.

[0021]

As described above, the present invention can measure the intensity of chemiluminescence generated by the extremely sensitive reaction of humic acid with hydrogen peroxide and formaldehyde.
Since this is a quantitative method that directly detects the presence of humic acid in a sample, it is possible to perform quantification of humic acid with high accuracy and rapidly.

Therefore, this method can be applied to quickly obtain accurate data for controlling the amount of chlorine added to waterworks, and it can be said that the industrial utility value of the present invention is extremely high. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a quantitative device of an experimental example.

FIG. 2 Luminous intensity-humic acid concentration bilogarithmic calibration curve diagram

[Explanation of symbols]

 A Humic acid-containing sample 4 Hydrogen peroxide water 6 Formaldehyde aqueous solution

Claims (1)

[Claims] 1. Hydrogen peroxide and formaldehyde are added to a humic acid-containing sample to cause chemiluminescence, and the emission intensity at a predetermined wavelength in the emission spectrum is measured by converting it into an electric signal by a photoelectric tube, and the emission intensity is separately measured. A humic acid quantification method using chemiluminescence in which luminescence intensity at a predetermined wavelength is compared with a humic acid concentration calibration curve for quantification.