KR20130088470A - Spectrophotometric determination of anionic surfactants in seawater and environmental water samples by solvent extraction using the mixed solvents of mibk-edc - Google Patents

Abstract

PURPOSE: A spectrophotometric quantitation of an anionic surfactant is provided to reduce analysis time to 1/3, the dose of a solvent to 1/2, and the size of an analysis container to 1/2, thereby largely reducing analysis time and cost. CONSTITUTION: A spectrophotometric quantitation of an anionic surfactant comprises the steps of: adding a pretreatment reagent, a methylene blue (MB) solution, and a mixture (MIBK-EDC) of methyl isobutyl ketone and 1,2-dichloroethane to seawater or an environmental water sample and mixing and incubating the primary mixture; removing an aqueous layer from the incubated mixture, adding primary washing water, and mixing and incubating the secondary mixture; adding secondary washing water and mixing and incubating the tertiary mixture; removing an aqueous layer from the tertiary mixture and filtering the remaining liquid; and measuring absorbance of the remaining liquid. [Reference numerals] (AA) Sample; (BB) Pretreatment reagent; (CC) Extraction (Mixing/Incubation); (DD,GG,JJ) Remove an aqueous layer; (EE) Primary washing water; (FF,II) Washing(Mixing/Incubation); (HH) Secondary washing water; (KK) 1ps filter paper; (LL) Filter; (MM) Measure absorbance

Description

Spectrophotometric determination of anionic surfactants in seawater and environmental water samples by solvent extraction using the mixed solvents of MIBK-EDC}

The present invention relates to a spectroscopic quantitative method of anionic surfactants contained in seawater and / or environmental water samples by MIBK-EDC mixed solvent extraction method, and more specifically, pretreatment reagent, methylene blue in seawater and / or environmental water samples. adding (methylene blue, MB) solution, a mixture of methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) (MIBK-EDC), mixing and standing; Removing the water layer from the stationary material, and then adding and washing the first washing water and then standing still; Removing the water layer obtained after adding the first wash water, and then adding and mixing the second wash water, and then standing still; And removing the aqueous layer obtained by adding the second wash water, and then filtering the filtrate to measure the absorbance of the filtrate. The powder of the anionic surfactant contained in the seawater and environmental water samples by the MIBK-EDC mixed solvent extraction method comprising a It relates to an optical quantification method.

Water is one of the ingredients that humanity needs to live.

Such water is an essential ingredient necessary for maintaining the homeostasis of water in addition to the intake of nutritional components required by the human body.

There are large amounts of seawater and fresh water on the earth, and the water that can be consumed by humans is fresh water, which can be obtained in the form of groundwater, valley water, river water and glacial water.

Meanwhile, as the industry develops, various products are produced, and water is used for various reasons in the production of such products, and the water used after the production of the product is discharged in the form of waste water, and the waste water can be used again by humans due to various treatments. Is being processed.

In particular, wastewater can be discharged through the ground and contaminate groundwater, valley water, and river water. Therefore, such wastewater should be discharged by removing components that threaten humans.

Water can contain many components, especially water-containing components, which may contain components that are good for the human body and / or are harmful to the body, so the components of the water should be measured regularly.

As such, there are various measurement methods depending on the components contained in the water, and in particular, the method of measuring the anionic surfactant components contained in the water, and the groundwater and river water specified in the current water pollution process test standard (Ministry of Environment, 2008). There is a method for analyzing anionic surfactants in water samples such as water, sewage, and wastewater.

The anion surfactant analysis method of the water sample is spectroscopically quantified by extracting methylene blue active substances (MBAS), an ion-pairing substance produced by the reaction of anionic surfactant and methylene blue, with chloroform, an organic solvent. .

Anionic surfactants (AS) react with methylene blue (MB), a cationic colorant, to form MBAS, an ion pair material (see Equation 1). Since MBAS is electrically neutral, when an organic solvent is added, it is distributed to the aqueous layer and the organic solvent layer by the difference in the distribution coefficient between water and the organic solvent. At this time, the amount of MBAS distributed to the organic solvent layer, that is, the extraction efficiency is determined according to the physicochemical characteristics of the organic solvent.

...식(1)

... (1)

In the current water quality testing standard, chloroform is used as the extraction solvent of MBAS. Due to the physico-chemical properties of chloroform, long analysis time, large amount of extraction solvent, and separation filter that double the number of samples are required. That is, (1) due to the low extraction efficiency of chloroform, two to three repetitive extraction processes are required. (2) The washing process is essential to remove the effects of the interfering substances. Since the specific gravity of chloroform is greater than water, the MBAS extract is located at the bottom of the separatory filter when it is extracted. . (3) Due to the high volatility of chloroform, it is necessary to remove the chloroform vapor during extraction and to adjust the volume of the extraction filtrate equally before measuring the absorbance after extraction. However, if the extraction solvent, the specific gravity is smaller than the water, and the extraction efficiency of MBAS is higher than that of chloroform, and the volatile is low, the solvent can be quickly analyzed and washed conveniently, and the amount of solvent consumption and separation filter can be reduced. have. That is, (1) if the extraction efficiency of the MBAS extraction solvent is excellent, it is not necessary to repeat the extraction process. (2) If the density of the extraction solvent is less than water, the extraction solvent layer is located at the top of the separation filter, so that it can be quickly washed and multi-stage washing. (3) If the extraction solvent has low volatility, it is not necessary to remove steam or adjust the volume of the extraction filtrate.

FIG. 1 shows a flowchart of a process for analyzing anionic surfactants contained in water using chloroform, which is defined as a standard method in water pollution test standards, as an extraction solvent.

In Figure 1, the <pretreatment> process is a process for removing impurities generated by oxidation of methylene blue in an alkaline state. This red impurity shows absorbance even at 650 nm, which is the measurement wavelength of MBAS. Therefore, in order to obtain accurate results, it is necessary to carefully remove impurities, which increases the analysis time and wastes the extraction solvent chloroform. In particular, the higher the temperature, the greater the amount of impurities produced and the rate of formation, which makes it more difficult to remove impurities in the hot summer months, increasing the likelihood of errors. In addition, when the <pretreatment> process is completed, the extract must be moved to the <cleaning> process quickly to minimize the generation of impurities, so the number of samples that can be analyzed at one time also occurs.

In the <extraction> process of FIG. 1, the analysis time is increased because two extractions have to be performed due to the low recovery rate of MBAS. In the <washing> process, a separate separation filter for washing is additionally required. Occurs. In the <filtration> process, the volume of the filtrate needs to be the same because the volume of the filtrate varies from sample to sample due to the high volatility of the chloroform and the easily generated emulsion, which results in a longer analysis time and additional chloroform. The required problem arises.

That is, the method of analyzing the anionic surfactant contained in the water shown in FIG. 1 requires a lot of analysis time and a separation filter that is twice as large as the extraction solvent and the number of samples due to the characteristics of the extraction solvent chloroform, and the analysis process is complicated. As well as the possibility of error occurrence, there is a problem such that the application is limited to samples such as seawater having a high chlorine ion concentration.

Accordingly, the present invention has been made to solve the above-mentioned problems, methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (1,2) instead of chloroform as an extraction solvent when analyzing anionic surfactants. -dichloroethane, EDC) powder of anionic surfactant in water, characterized in that a mixed solvent (MIBK-EDC) is used in which the volume ratio is 4: 1-7: 3, preferably 3: 1. An optical quantification method is provided.

In particular, according to the present invention, as the extraction solvent used in the analysis of anionic surfactants of conventional water samples is changed, a process for analyzing anionic surfactants, analytical reagents, etc., is also newly used to quickly and conveniently the content of anionic surfactants in various water samples. We want to provide a way to analyze it.

When the extraction solvent is changed, the type and concentration of the interferences to be extracted also vary according to the physicochemical properties of the extraction solvent. Therefore, a method of removing the interferences by applying a new extraction solvent should be taken. Therefore, in the present invention, the influence of the interference material on the measurement result was minimized through the method of (1) ion pair generation blocking, (2) ion pair removal, and (3) ion pair destruction of the interference material.

(1) Blocking ion pair generation: In order for the interference material to affect the measurement result, ion pairs must be formed with methylene blue. Therefore, by changing the electrical charge state of the interference material, it is possible to block the generation of ion pairs of the interference material. Extraction before when the sample liquid of the acid, cyanide ion (CN ^-), or, as in the case of acid ion some of the interfering substance is a reaction changing the charged state is electrically neutral in combination with the hydrogen ions (H ⁺⁾ up these interferents The effect of is reduced. In addition, in the acidic state, the addition of methylene blue does not produce dimethylthionoline, which is a red impurity. Therefore, it is unnecessary to remove methylene blue impurities before taking samples as in the standard method of the water pollution test standard.

(2) Ion pair removal: Since ion pairs of interfering substances have a smaller distribution coefficient than ion pairs of anionic surfactants, ion pairs of interfering substances mixed in the extraction process can be removed by using the difference of distribution coefficients. . When distilled water is added to the extract, some of the ion pairs of the anionic surfactant and the ion pairs of the interfering substances move from the organic solvent layer to the water layer, and the proportion of the interfering substances to the water layer is higher because of the relatively smaller partition coefficient of the interfering substances. . Repeating this process can remove most of the ion pairs of the interfering substances, but the increase in the number of times the analysis time is long, the problem occurs that the sensitivity is reduced, the present invention was limited to two times. Interfering substances such as nitrite ions or nitrate ions which are not affected by pH can be effectively removed through this washing process.

(3) Ion pair destruction: In order to maximize the removal efficiency of interfering substances by two washes, the composition of primary and secondary wash water was optimized to be suitable for ion pair destruction. Solvent extraction in an acidic state may increase interference with some interfering materials. In the case of hydrogen phthalate ion, the type of monovalent anion is increased in acid, so the interference is increased by solvent extraction in acid. However, when alkaline washing water is added to the extract containing the ion pairs of hydrogen phthalate ions, the hydrogen phthalate ions are converted to phthalate ions and the electrical neutrality is broken, resulting in the destruction of the ion pairs, thereby reducing interference. In the present invention, in order to minimize the influence of interference materials having properties such as hydrogen phthalate ions, the primary washing water is prepared in an alkaline manner. At this time, the higher the pH of the washing water is advantageous to remove interference, but when the pH is too high, methylene blue is oxidized to red impurities, so a buffer solution of pH 9.2 was used to prevent this. On the other hand, some of the interferences, such as iodine ions or salicylic acid ions are not easily removed by pH control or two washes. Substances that can react with these interferences to form stable complexes are added to the secondary wash water to destroy the ion pairs of the interferences. Since the solubility product constant between silver ions (Ag ⁺ ) and interferences such as chlorine, bromine, iodine, thiocyan, and cyan ions is very small, excess silver ions may be present even at low concentrations. Ag ⁺ ) forms precipitates easily. Salicylate ions are known to form stable complexes with aluminum (Al) ions. Accordingly, in the present invention, [silver sulfate (Ag ₂ SO ₄ ) -potassium alum (AlK (SO ₄ ) ₂ ) mixed solution] was used as the second washing water to minimize the influence of these interferences.

Currently, the standard method of water pollution test standards has various problems due to the physicochemical properties of chloroform used as an extraction solvent. Due to the low MBAS extraction efficiency, it is necessary to repeat extraction 2-3 times, and it is heavier than water, so it requires separate separation filter for washing, and the extraction time is long. Since the loss varies from sample to sample, it is necessary to adjust the volume of the extraction filtrate equally before measuring the absorbance. As these various problems work in combination, the standard method requires a lot of analysis time, an extraction solvent and an analysis container, and the possibility of error is high.

In particular, the standard method of the current process test standard adopts a method of solvent extraction in an alkaline state in order to remove the interference of substances originating from proteins. In alkaline state, methylene blue is converted into red impurities and affects the measurement result. Since it is crazy, the pretreatment to completely remove this impurity with chloroform is prescribed, which is the biggest factor to prolong the analysis time.

Accordingly, the present invention provides a method for spectroscopic quantification of anionic surfactants contained in seawater and environmental water quality samples by MIBK-EDC mixed solvent extraction method that can solve the above problems.

The present invention adds and mixes a pretreatment reagent, a methylene blue (MB) solution, a mixture of methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) (MIBK-EDC) to seawater and / or environmental water samples. Then stationary; Removing the water layer from the stationary material, and then adding and washing the first washing water and then standing still; Removing the water layer obtained after adding the first wash water, and then adding and mixing the second wash water, and then standing still; And removing the aqueous layer obtained by adding the second wash water, and then filtering the filtrate to measure the absorbance of the filtrate. Optical quantification method can be provided.

In more detail, the above-mentioned contents of the present invention are described in more detail, where specific gravity is lighter than water, MBAS extraction efficiency is similar to chloroform, and volatile is methyl isobutyl ketone (MIBK) with only 1/7 level of chloroform and specific gravity is higher than water. Larger but smaller than chloroform, MBAS extraction efficiency is 20% higher than chloroform, but 1,2-dichloroethane (EDC) with 3/7 volatility is mixed in a 3: 1 ratio, lighter than water and extracted than chloroform A high efficiency, short layer separation time, low emulsion generation, and low volatility MIBK-EDC mixed solvent were prepared and used as the extraction solvent of MBAS.

If the MIBK-EDC mixed solvent is used as the extraction solvent, the extraction efficiency of one extraction is higher than that extracted with chloroform two or three times in the standard method, and thus it is not necessary to perform repeated extraction. In addition, because the extraction solvent is lighter than water, it is located above the separatory filter, so no separate filter filter is required for washing, and because the volatility is low, the process of removing steam during extraction and washing and the volume of the extract filtrate after extraction No adjustment is necessary. Therefore, analysis time, solvent usage and container requirements can be reduced.

On the other hand, if the extraction solvent is changed according to the physico-chemical characteristics of the extraction solvent, the type and amount of the interference material is also changed, so an effective method of removing the interference material should be devised. In order to minimize the influence of interferences due to the change of extraction solvent, this study newly established the analytical process and used pretreatment agent and primary and secondary wash water for the purpose of blocking, destroying or removing ion pairs. Developed and applied to the analysis.

As a first step to minimize the influence of interferences, acidic pretreatment was added to minimize the generation of ion pairs of interferences such as cyan and salicylic acid. In addition, by adjusting the pH of the sample to acidic, it was possible to simplify the analysis process, shorten the analysis time, and significantly reduce the solvent consumption by omitting the standard method of <removing impurities according to alkaline extraction>. In addition, this process can be expected to have an interference cancellation effect similar to that of <acid-extraction> in the Standard Method (APHA, 1998).

Next, interferences with small distribution coefficients were removed using the difference of distribution coefficients through two-stage washing. In this process, the composition of the primary and secondary wash water was optimized to be suitable for the ion pair destruction in consideration of the physicochemical properties of the interfering substances, thereby minimizing the influence of various interfering substances. First, <alkaline-washing> was performed using primary wash water prepared with alkaline buffer solution, thereby reducing interference of interference materials such as hydrogen phthalate ion. Through this process, interference cancellation effects similar to those of <alkali extraction> in the standard method or ISO (7875-1, 1996) can be expected. Next, using silver (Ag ₂ SO ₄ ) -potassium alum (AlK (SO ₄ ) ₂ ) mixed solution) as secondary washing water, interference with chlorine ion, bromine ion, iodine ion, cyan ion and salicylic acid ion Could be effectively removed.

Compared with the standard method of water pollution process test criteria, the present invention requires only 1/3 analysis time and 1/2 solvent usage, and only 1/2 of the analysis container is required, thereby greatly reducing analysis time and cost. have. In addition, the detection limit of the anionic surfactant is lower than that of the standard method, the extraction efficiency is high, the influence of the interference materials is low, and the reproducibility is good, so that accurate and precise analysis is possible.

Accordingly, it can be applied to most wastewater samples including natural water such as groundwater, river water and lake water, as well as domestic sewage and car wash waste water. In particular, the present invention has been developed to effectively remove the interference of halogen anion ions, so that high concentrations of chlorine ions, such as sea water, are widely used in high salt samples, which have limited application of standard methods of water pollution testing standards. Applicable

1 is a flow chart of a process for analyzing anionic surfactants contained in seawater and / or environmental water quality samples using chloroform, which is defined as a standard method in the water pollution process test standard, as an extraction solvent.
2 is a flowchart of a process for analyzing anionic surfactants contained in seawater and / or environmental water quality samples using MIBK-EDC of the present invention as an extraction solvent.

The present invention shows a spectroscopic quantitative method for anionic surfactants contained in seawater and environmental water quality samples by the MIBK-EDC mixed solvent extraction method.

The present invention adds and mixes a pretreatment reagent, a methylene blue (MB) solution, a mixture of methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) (MIBK-EDC) to seawater and / or environmental water samples. Then stationary; Removing the water layer from the stationary material, and then adding and washing the first washing water and then standing still; Removing the water layer obtained after adding the first wash water, and then adding and mixing the second wash water, and then standing still; And removing the aqueous layer obtained by adding the second wash water, and then filtering the filtrate to measure the absorbance of the filtrate. The powder of the anionic surfactant contained in the seawater and environmental water samples by the MIBK-EDC mixed solvent extraction method comprising a Optical quantification method is shown.

For 100 ml of seawater and / or environmental water samples, 5-30 ml of pretreatment reagent, 5-15 ml of 0.01-0.03% methylene blue (MB) solution, methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) 20 to 70 ml of a mixture of (MIBK-EDC) can be added, mixed and then left to stand.

For 100 ml of seawater and / or environmental water samples, 20 ml of pretreatment reagent, 5 ml of 0.025% methylene blue (MB) solution, a mixture of methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) (MIBK-EDC) ) 50 ml may be added, mixed and left to stand.

The seawater and / or environmental water quality sample may be any one selected from ground water, river water, lake water, sewage water, waste water, and sea water. .

In the above pretreatment reagent, 20-50 g of magnesium sulfate (MgSO ₄ ) is dissolved in 400-500 ml of distilled water, 25-25 ml of 0.25M-1.0M sulfuric acid (H ₂ SO ₄ ) is added, and distilled water is added to the total reagent volume of 1000 ml. Can be used.

In the above pretreatment reagent, 49.3 g of magnesium sulfate (MgSO ₄ ) is dissolved in 500 ml of distilled water, 50 ml of 0.5 M sulfuric acid (H ₂ SO ₄ ) is added, and distilled water is added so that the total reagent volume is 1000 ml.

In the above-described methylene blue (MB) solution, 0.1-0.3 g of methylene blue is dissolved in 400-600 ml of distilled water, 5-20 ml of 0.25 M-1.0 M sulfuric acid (H ₂ SO ₄ ) is added, and distilled water is added to the total reagent volume. Can be used to make 1000ml.

In the above methylene blue (MB) solution, 0.25 g of methylene blue was dissolved in 500 ml of distilled water, 10 ml of 0.5 M sulfuric acid (H ₂ SO ₄ ) was added, and distilled water was added so that the total reagent volume was 1000 ml. .

As the mixture of methyl isobutyl ketone and 1,2-dichloroethane, a mixture of methyl isobutyl ketone: 1,2-dichloroethane in a volume ratio of 4: 1 to 7: 3 may be used.

As the mixture of methyl isobutyl ketone and 1,2-dichloroethane, a mixture of methyl isobutyl ketone: 1,2-dichloroethane in a volume ratio of 3: 1 may be used.

After removing the aqueous layer of the stationary water in the above 20 to 70 ml of the first washing water may be added and mixed and then left to stand.

After removing the aqueous layer of the still water in the above 50ml of the first washing water may be added and mixed and then left to stand.

In the first wash water may be mixed with 800ml of distilled water 1M NaHCO ₃ 40-50ml and 0.4M Na ₂ CO ₃ 1-10ml after adding distilled water so that the volume of the first wash water to 1000ml.

The first washing water may be mixed with 800ml of distilled water, 46ml of 1M NaHCO ₃ and 10ml of 0.4M Na ₂ CO ₃ and then added to the distilled water so that the volume of the primary wash water to 1000ml.

After removing the aqueous layer of the stationary material obtained after the addition of the first wash water, 20 to 70 ml of the second wash water may be added and allowed to stand.

After removing the aqueous layer of the stationary material obtained after the addition of the first wash water, 50 ml of the second wash water may be added and allowed to stand.

The secondary wash water is dissolved in silver sulfate (Ag ₂ SO ₄ ) 0.5 ~ 2.5g and potassium alum (AlK (SO ₄ ) ₂ ) 1 ~ 3g in 750 ~ 850ml of distilled water and warmed to a temperature of 60 ~ 80 ℃ After cooling to room temperature of 20-25 degreeC, distilled water was added and the volume of the secondary wash water may be 1000 ml.

In the second wash water, 1 g of silver sulfate (Ag ₂ SO ₄ ) and ₂ g of potassium alum (AlK (SO ₄ ) ₂ ) are added to 800 ml of distilled water, warmed to a temperature of 60 to 80 ° C., and then dissolved at room temperature of 20 to 25 ° C. After cooling, distilled water may be added so that the volume of the secondary washing water is 1000 ml.

After the addition of the second wash water, the aqueous layer obtained is removed and then filtered to measure the absorbance of the filtrate at 650 ~ 660nm by ultraviolet / visible spectrophotometer.

After the addition of the second wash water, the aqueous layer obtained can be removed and filtered to measure the absorbance of the filtrate at 658 nm with an ultraviolet / visible spectrophotometer.

The spectroscopic quantitative determination of anionic surfactants contained in seawater and environmental water samples by the MIBK-EDC mixed solvent extraction method of the present invention was carried out under various conditions, in order to achieve the object of the present invention by the above-mentioned conditions. It is desirable to provide a method for spectroscopic quantification of anionic surfactants contained in seawater and environmental water quality samples by the MIBK-EDC mixed solvent extraction method.

Hereinafter, the content of the present invention will be described in detail through Experimental Examples and Examples. However, these are for the purpose of illustrating the present invention in more detail, and the scope of the present invention is not limited thereto.

<Experimental Example>

In order to solve the problems of the standard analytical method and to develop an analytical method capable of quantitating anionic surfactants quickly and accurately, the present inventors have conducted numerous experiments and studies over a long period of time, and as a result, MIBK is an extraction solvent that can replace chloroform. -EDC mixed solvent and a new experimental method were developed. The contents are as follows.

1. Physicochemical Properties of MIBK-EDC Mixed Solvents

In the present invention, a new extraction solvent was first developed to replace chloroform, which is an extraction solvent of MBAS. MBAS extraction efficiency and physicochemical characteristics of various organic solvents were investigated.Methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) were mixed at a ratio of 3: 1, which is lighter than water and more efficient than chloroform. The high but low layer separation time and low volatility was prepared MIBK-EDC mixed solvent, the characteristics are shown in Table 1 below. At this time, sodium dodecyl sulfate (SDS) was used as a standard material of the anionic surfactant.

Comparison of Extraction Characteristics and Physicochemical Properties of MIBK-EDC Mixed Solvents and Chloroforms division MIBK-EDC Chloroform Absorbance of 100 SG SDS 0.6995 0.5901 Separation time (minutes) 2.5 15 Density (g / mL) 0.91 1.48 Volatilization Rate (mL / min) 0.06 0.28

2. Method of Analysis

(1) Analysis process

① Take 100 mL of the sample (containing 0.10 mg or less as anionic surfactant), put it in the separating funnel, add 20 mL of pretreatment agent and 5 mL of 0.025% methylene blue solution, and mix well.

② Add 50mL of MIBK-EDC mixed solvent, shake for 30 seconds and mix.

③ After removing the aqueous layer, add 50 mL of the first washing water to the remaining mixed solvent layer and mix for 30 seconds.

④ After removing the water layer, add 50 mL of the second wash water to the remaining mixed solvent layer, mix and leave for 30 seconds.

⑤ After removing the water layer, the remaining mixed solvent layer is filtered using a liquid separation filter (No. 1PS, Whatman) treated with silicon, and handwritten to a test tube with a stopper.

⑥ Measure the absorbance of the extraction filtrate at 658nm using UV / VIS spectrophotometer.

* Preparation of calibration curve: Take 0.5-10mL of 10mg / L SDS solution step by step and test according to the test method of sample, and prepare the relationship line between the amount of anionic surfactant and absorbance.

(2) Reagent

① MIBK-EDC mixed solvent: A mixed solvent of Methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) in a volume ratio of 3: 1 was used.

② 0.025% methylene blue solution: 0.25g of methylene blue (methylene blue trihydrate) was dissolved in distilled water, 0.5MH ₂ SO ₄ 10mL was added and distilled water was added so that the final volume of 1 liter (L) was used. .

③ Pretreatment: Dissolve 49.3 g of magnesium sulfate heptahydrate (MgSO4 · 7H2O) in 500 mL of distilled water, add 50 mL of 0.5 MH ₂ SO ₄ , and add distilled water so that the final volume was 1 liter (L). .

④ 1st wash water: 46 ml of ₁ M NaHCO ₃ and 10 ml of 0.4 M Na ₂ CO ₃ were added to 800 ml of distilled water, mixed well, and distilled water was added so that the final volume was 1 liter (L). (PH 9.2)

⑤ Second wash water: 1g of silver sulfate (Ag ₂ SO ₄ ) and 2g of potassium alum (AlK (SO ₄ ) ₂ ) were dissolved in 800mL of distilled water at 70 ℃, and then dissolved at 25 ℃. The mixture was cooled to room temperature and distilled water was added so that the final volume was 1 liter (L).

(3) Detection limit and quantitative limit

The detection limit and quantitative limit of the method calculated by Wisconsin Department of Natural Resources (1996) were 0.25 µg and 0.79 µg in distilled water and 0.27 µg and 0.89 µg in seawater, respectively. The quantitative range of this method is 1 to 100 µg as an anionic surfactant, and when tested according to this method, the effective measurement concentration is 0.01 mg / L or more.

3. Comparison with standard analysis methods and verification

(1) Comparison with standard analysis methods

Table 2 compares the standard method using chloroform as the extraction solvent and the new method using MIBK-EDC as the extraction solvent. As shown in the table, the analysis time was reduced by one-third compared to the existing method by applying the new analysis method, the extraction solvent requirement was reduced to 1/2 level, and the separation margin requirement was reduced to 1/2 level. In addition, the calibration curve slope of SDS, a standard of anionic surfactant, was increased by about 18%.

Comparison of Chloroform Extraction Method and MIBK-EDC Extraction Method division MIBK-EDC
Extraction Method Chlororoform
Extraction Method Remarks Analysis time (minutes) 90 270 1/3 reduction Solvent Requirement (mL) 600 1390 Cut to 1/2 Analytical container requirements () 12 36 1/3 reduction Slope of calibration curve
(slope of SDS μg vs abs) 0.00690 0.00583 18% increase

Table 3 below shows the influence of the interferences in the MIBK-EDC assay. In the case of exceeding the effective measurement concentration of 0.02mg / L of the conventional anionic surfactant analysis method, the effective interference concentration that may affect the measurement result is 0.5M for fluorine ion, 1.0M for chlorine ion and bromine ion. 0.5M silver, iodine ion 0.001M, nitrite ion 1.0M, nitrate ion 0.01M, phosphate ion 1.0M, bicarbonate ion 1.0M, cyan ion 0.1M or less It did not appear to affect.

Influence of Interferences in MIBK-EDC Assay compound Interference Treatment concentration
(M) Measurement result (mg / L) Interference concentration Standard Deviation NaF F ^- 0.5 0.002 0.001 NaCl Cl ^- 1.0 0.007 0.002 KBr Br ^- 0.01 0.002 0.001 0.5 0.016 0.002 KI I ^- 0.0002 0.005 0.003 0.001 0.011 0.000 NaNO ₂ NO ₂ ^- 0.25 0.009 0.003 1.0 0.013 0.005 KNO ₃ NO ₃ ^- 0.01 0.001 0.002 KH ₂ PO ₄ H ₂ PO ₄ ^- 1.0 0.007 0.001 NaHCO ₃ HCO ₃ ^- 1.0 0.010 0.000 KCN CN ^- 0.1 0.007 0.002

Example 1 SDS Recovery Test in River Water

In order to test the recovery rate of the sample containing the anionic surfactant using the MIBK-EDC solvent for each sample to which a certain amount of SDS was added to the sample shown in Table 4, the prepared sample was prepared by adding a certain amount of standard SDS to the river water. It was analyzed by the method of and the results are shown in Table 4.

(1) Measurement of recovery rate of sample

① 100 mL of the sample was put into the separating filter, and 20 mL of the pretreatment agent and 5 mL of 0.025% methylene blue solution were added and mixed well.

② 50 mL of MIBK-EDC mixed solvent was added, shaken for 30 seconds, and allowed to stand.

③ After removing the aqueous layer, 50 mL of the first washing water was added to the remaining mixed solvent layer, followed by mixing for 30 seconds and standing.

④ After removing the aqueous layer, 50 mL of secondary washing water was added to the remaining mixed solvent layer, and the mixture was allowed to stand for 30 seconds.

⑤ After removing the water layer, the remaining mixed solvent layer was filtered using a silicon-treated liquid separation filter (No. 1PS, Whatman).

⑥ The absorbance of the extract filtrate was measured at 658 nm using a UV / VIS spectrophotometer.

(2) Reagent

① MIBK-EDC mixed solvent: A mixed solvent of Methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) in a volume ratio of 3: 1 was used.

② 0.025% methylene blue solution: 0.25g of methylene blue (methylene blue trihydrate) was dissolved in distilled water, 0.5MH ₂ SO ₄ 10mL was added and distilled water was added so that the final volume of 1 liter (L) was used. .

③ Pretreatment: Dissolve 49.3 g of magnesium sulfate heptahydrate (MgSO4 · 7H2O) in 500 mL of distilled water, add 50 mL of 0.5 MH ₂ SO ₄ , and add distilled water so that the final volume was 1 liter (L). .

④ 1st wash water: 46 ml of ₁ M NaHCO ₃ and 10 ml of 0.4 M Na ₂ CO ₃ were added to 800 ml of distilled water, mixed well, and distilled water was added so that the final volume was 1 liter (L). (PH 9.2)

⑤ Second wash water: 1g of silver sulfate (Ag ₂ SO ₄ ) and 2g of potassium alum (AlK (SO ₄ ) ₂ ) were dissolved in 800mL of distilled water at 70 ℃, and then dissolved at 25 ℃. The mixture was cooled to room temperature and distilled water was added so that the final volume was 1 liter (L).

The river water samples used for the recovery rate test were taken from two main streams of the well-known stream located in Chuncheon-si, Gangwon-do and the ends of the tributaries. As shown in Table 4, the SDS recovery rate was 100 to 102% in the river water.

SDS Recovery Test in River Water sample
number Name of sample Anionic Surfactant Content
(mg / L) SDS
Addition amount
(㎍) Measurement result density
(㎍) Standard Deviation
(㎍) CV
(%) Recovery
(%) One Sinchoncheon 0.009 20 20.9 0.5 2.4 100.0 2 Hakgokcheon 0.006 60 61.7 0.2 0.4 101.8 3 Geodukcheon 0.005 40 41.1 0.8 1.8 101.5 4 Gongjicheon-Master's Bridge 0.006 80 80.9 0.8 1.0 100.4 5 Toegyecheon 0.021 100 102.1 0.5 0.5 100.0 6 Gongjicheon-Gongji Bridge 0.023 120 122.4 0.8 0.7 100.1

Example 2 SDS Recovery Test in Seawater

As described in Example 1, the recovery rate of the sample (1), the recovery rate of the SDS of the seawater using the reagent (2) was assayed and the results are shown in Table 5 below.

The seawater used for the experiment was collected from the beach near Namhangjin Port, Gangneung-si, Gangwon-do and stored at room temperature (25 ℃) for 10 months.

As shown in Table 5, the MBAS concentration of the seawater sample without SDS was less than 0.01 mg / L, which was below the effective interference concentration. The recovery rate of the sample with SDS was 101-104%, indicating a deviation within 5%. It was investigated.

SDS recovery rate in seawater SDS addition amount (㎍) Measurement result (㎍) % Recovery 0 0.5 - 20 20.6 101 40 41.8 103 60 62.7 104 80 83.4 104 100 103.8 103 120 124.2 103

On the other hand, the measurement results of the SDS with respect to the addition amount of the SDS in Table 5 is shown in Figure 3, in Figure 3 between the addition amount of the SDS (X: ㎍) and the measurement result (Y: ㎍) Y = 1.003Ｘ + 0.38 (r ² = 0.99999).

Example 3 Recovery Rate Test in Sewage Sample

100 mL of each sewage effluent shown in Tables 6 and 7 was added to a separatory filter, and 20 mL of a pretreatment agent and 5 mL of 0.025% methylene blue solution were added and mixed well. After standing, the aqueous layer was removed, and then 50 mL of the first washing water was added to the remaining mixed solvent layer, followed by mixing for 30 seconds. After removing the aqueous layer, the remaining mixed solvent layer was filtered using a silicon-treated liquid separation filter (No. 1PS, Whatman), and then the absorbance of the filtrate was extracted using an UV / VIS spectrophotometer. Was measured at 658nm to measure the recovery rate of the anionic surfactant and the results are shown in Table 6 and Table 7.

In the MIBK-EDC mixed solvent, a mixed solvent of Methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) in a volume ratio of 3: 1 was used.

In the above 0.025% methylene blue solution, 0.25 g of methylene blue (methylene blue trihydrate) is dissolved in distilled water, 0.5MH ₂ SO ₄ 10mL is added, and distilled water is added so that the final volume is 1 liter (L). It was.

In the above pretreatment, 49.3 g of magnesium sulfate heptahydrate (MgSO 4 · 7H ₂ O) was dissolved in 500 mL of distilled water, 50 mL of 0.5MH ₂ SO ₄ was added thereto, and the final volume was added so that the final volume was 1 liter (L). It was.

In the first wash water, 46 mL of 1M NaHCO ₃ and 10 mL of 0.4M Na ₂ CO ₃ were added to 800 mL of distilled water, and the mixture was mixed well, and distilled water was added so that the final volume was 1 liter (L). (PH 9.2)

The secondary washing water is dissolved 1 g of silver sulfate (Ag ₂ SO ₄ ) and ₂ g of potassium alum (AlK (SO ₄ ) ₂ ) in 800 mL of distilled water to a temperature of 70 ° C., followed by 25 ° C. Was cooled to room temperature and distilled water was added so that the final volume was 1 liter (L).

Meanwhile, the recovery rate of the anionic surfactant for each sewage effluent shown in Table 6 and Table 7 was measured using the standard method of water pollution process test standard using chloroform as the extraction solvent described in FIG. Table 6 and Table 7 are shown.

Table 6 and Table 7 below show the measurement results of the recovery rate of the anionic surfactant by the respective analytical methods using the mixed solvent MIBK-EDC and chloroform for the sewage effluent. The sample used sewage discharged water which was inspected by Gangwon-do Institute of Health and Environment. The measurement results of the two methods for sewage effluent show deviations of ± 0.02 mg / L, indicating little difference between the two methods.

Comparison of Analysis Results for Sewage Effluent Samples No. Name of sample MIBK-EDC
(mg / L) Chlororoform
(mg / L) One Sokcho 0.019 ND ⁺ 2 Hongcheon-gun 0.023 0.016 3 Chuncheon 0.024 0.015 4 Chuncheon Gangchon 0.019 ND ⁺ 5 Chuncheon Seomyeon 0.028 0.016 6 Chuncheon Sinbuk 0.042 0.041 7 Yeongwol Mokgol 0.020 0.009

* ND: Not Detection

Comparison of Analysis Results for Sewage Effluent Samples No. Name of sample MIBK-EDC
(mg / L) Chlororoform
(mg / L) 8 Yeongwol Hot 0.030 0.029 9 Wonju Sillim 0.015 0.013 10 Yanggu-gu 0.113 0.124 11 Yanggu School 0.045 0.043 12 Yanggu Bay 0.033 0.039 13 Hongcheon Sokcho 0.028 0.031 14 Attracting Hongcheon 0.021 0.019

On the other hand, the correlation between the recovery results of the anionic surfactants by the respective analytical methods using the mixed solvent MIBK-EDC as the extraction solvent and chloroform for the sewage treatment plant effluent is shown in FIG.

As shown in FIG. 4, between the measured value X of the anionic surfactant using the mixed solvent MIBK-EDC and the value Y of the anionic surfactant using the chloroform [Y = 1.080X-0.003, r ² = 0.9993] A very high correlation was found.

Example 4 Recovery Rate Test in Car Wash Wastewater Sample

Anion surfactants were quantified using the MIBK-EDC mixed solvent mentioned in Example 3 on the car wash waste water samples tested by Kangwondo Institute of Health and Environment. Also, the anionic surfactants were quantified using chloroform and the results were obtained. 5 is shown.

As shown in Figure 5 between the quantitative analysis value of the anionic surfactant of the car wash wastewater sample using chloroform and the anionic surfactant of the car wash wastewater sample using the mixed solvent MIBK-EDC [Y = 1.0456X -0.0169, r ² = 0.9796].

As in the results of the above Experimental Examples and Examples, the spectroscopic quantification method of the anionic surfactant contained in the water of the present invention does not have a large difference in the measurement result compared with the standard method of the water pollution test standard, The time is 1/3, solvent use is only 1/2, and the analytical container requires only 1/2, which can greatly reduce analysis time and cost. In addition, the detection limit of the anionic surfactant is lower than that of the standard method, the extraction efficiency is high, the influence of the interference materials is low, and the reproducibility is good, so that accurate and precise analysis is possible. Accordingly, it can be applied to most wastewater samples including natural water such as groundwater, river water and lake water, as well as domestic sewage and car wash waste water. In addition, since the present invention was developed to effectively remove the interference of halogen anions, high concentrations of chlorine ions, such as sea water, have been extensively applied to high salt samples, which have limited application of standard methods of water pollution testing standards. Applicable

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. It will be understood that the invention may be modified and varied without departing from the scope of the invention.

Spectroscopic quantification method of the anionic surfactant contained in the water of the present invention compared to the standard method of the water pollution process test standard analysis time is 1/3, solvent use is only 1/2, the analysis container is 1/2 Only a small amount of analysis time and cost can be saved. In addition, the detection limit of the anionic surfactant is lower than that of the standard method, the extraction efficiency is high, the influence of the interference materials is low, and the reproducibility is good, so that accurate and precise analysis is possible.

Accordingly, it can be applied to most wastewater samples including natural water such as groundwater, river water and lake water, as well as domestic sewage and car wash waste water. In addition, since the present invention was developed to effectively remove the interference of halogen anions, high concentrations of chlorine ions, such as sea water, have been extensively applied to high salt samples, which have limited application of standard methods of water pollution testing standards. There is industrial applicability as it can be applied.

Claims (8)

Add a pretreatment reagent, a methylene blue (MB) solution, a mixture of methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) (MIBK-EDC) to the seawater or environmental water sample, mix and then stand ;
Removing the water layer from the stationary material, and then adding and washing the first washing water and then standing still;
Removing the water layer obtained after adding the first wash water, and then adding and mixing the second wash water, and then standing still; And
And removing the water layer of the stationary material obtained after adding the second wash water, and then filtering the filtrate to measure the absorbance of the filtrate. The method of claim 1,
A mixture of 5-30 ml of pretreatment reagent, 5-15 ml of 0.01-0.03% methylene blue (MB) solution, methyl isobutyl ketone (MIBK) and 1,2-dichloroethane (EDC) for 100 ml of seawater or environmental water samples (MIBK) -EDC) 20-70 ml are added, mixed and left to stand;
Removing the aqueous layer from the stationary material, and then adding 20 to 70 ml of the first washing water, mixing the mixture, and then standing still;
Removing the water layer obtained after adding the first wash water, and then adding 20-70 ml of the second wash water and leaving the still water; And
Removing the aqueous layer obtained after the addition of the second wash water, and then filtering and measuring the absorbance at 650 to 660 nm with an ultraviolet / visible spectrophotometer; spectroscopic quantitative method for anionic surfactants comprising a; . The method according to claim 1 or 2,
The seawater or environmental water quality sample is any one selected from ground water, river water, lake water, sewage water, waste water, and sea water. Spectroscopic quantitation method. The method according to claim 1 or 2,
For pretreatment reagent, dissolve 20-50 g of magnesium sulfate (MgSO ₄ ) in 400-500 ml of distilled water, add 25-100 ml of 0.25 M-1.0M sulfuric acid (H ₂ SO ₄ ), and add distilled water to make the total reagent volume 1000 ml. Spectroscopic quantitative method of anionic surfactant, characterized in that one. The method according to claim 1 or 2,
The methylene blue (MB) solution is dissolved in 0.1-0.3 g of methylene blue in 400-600 ml of distilled water, 5-20 ml of 0.25 M-1.0 M sulfuric acid (H ₂ SO ₄ ) is added, and distilled water is added. Spectroscopic quantification method of the anionic surfactant, characterized in that to be. The method according to claim 1 or 2,
The mixture of methyl isobutyl ketone and 1,2-dichloroethane is a spectroscopic quantitative method of anionic surfactant, characterized in that the mixture of methyl isobutyl ketone: 1,2-dichloroethane in a volume ratio of 3: 1. The method according to claim 1 or 2,
The first washing water is a mixture of 40-50 ml of 1M NaHCO _{3 and} 1-10 ml of 0.4M Na ₂ CO _{3 in} 800 ml of distilled water, and then distilled water is added to make the volume of the first washing water 1000 ml. Optical quantitation method. The method according to claim 1 or 2,
Secondary wash water was dissolved in silver sulfate (Ag ₂ SO ₄ ) 0.5-2.5g and potassium alum (AlK (SO ₄ ) ₂ ) 1-3g in distilled water 750-850ml and warmed to a temperature of 60-80 ℃ to dissolve. After cooling to room temperature of 25 ℃ distilled water was added to the volume of the second wash water spectroscopic quantitative method characterized in that the volume of 1000ml.

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