CN113848244A - Microcoulomb method for measuring adsorbable organic halogen in seawater - Google Patents
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Abstract
The application relates to the field of organic halogen detection, and particularly discloses a microcoulomb method for determining adsorbable organic halogen in seawater, which comprises the following steps: s1: collecting a seawater sample for later use; s2: pretreating a seawater sample by adopting a mechanical-assisted oscillation adsorption method to obtain a pretreated sample; s3: measuring the AOX value of the pretreated sample by using a microcoulometer, namely obtaining the AOX measured value; the method has the advantage of accurately detecting the adsorbable organic halogen in the seawater.
Description
Technical Field
The present application relates to the field of organohalogen detection, and more particularly, to a microcoulomb method for measuring adsorbable organohalogens in seawater.
Background
Organic halides are carcinogenic, teratogenic, mutagenic and have always been the focus of attention, for example, more than half of the 129 preferred pollutants proposed by the Environmental Protection Agency (EPA) are halogenated organics. However, due to the wide source and the wide molecular weight distribution range of the organic halide, the detection of each organic halide cannot be realized. At present, adsorbable organic halogen (AOX) is taken as a comprehensive index for reflecting the pollution level of organic halides in water and plays an important role in the pollution control of the organic halides.
The microcoulomb method is a common method for detecting AOX in a water sample, and according to the principle of detecting the AOX in the water sample by the microcoulomb method, the detection program is divided into three steps, firstly, target halogen is adsorbed on active carbon, inorganic halogen ions are eluted to remove interference, then, organic halogen is converted into inorganic hydrogen halide by means of high temperature and the like, and finally, the content of the inorganic hydrogen halide is quantitatively analyzed by the microcoulomb method to calculate the concentration of the AOX. Therefore, the elution and removal of inorganic halide ions is a prerequisite for the accurate measurement of AOX.
However, the conventional microcoulomb method is not suitable for determining the AOX content in seawater. Because the seawater contains abundant inorganic halogen ions, the content of chloride ions is over 20 g.L at most-1The content of bromide ion is more than 65 mg.L-1The content of iodide ion is more than 60 mug.L-1In the international current measuring standard method, specific restriction requirements are put forward on the content of inorganic chloride ions, for example, GB/T15959-1995 microcoulomb method for measuring organic halogen capable of being absorbed by water quality requires that the content of inorganic chloride ions is less than 1 g.L-1The method detection limit is 10 mu g.L-1Therefore, the test by directly sampling from seawater is certainly not in compliance with the test standard. And the concentration of AOX in seawater is generally dozens of micrograms to hundreds of micrograms per liter, even if the concentration of inorganic halogen ions is reduced in a dilution mode, the concentration of AOX in seawater is diluted too low to be detected.
Disclosure of Invention
In order to accurately and stably detect the concentration of AOX in seawater, the application provides a microcoulomb method for determining adsorbable organic halogen in seawater.
The microcoulomb method for measuring the adsorbable organic halogen in the seawater adopts the following technical scheme:
a microcoulomb method for measuring adsorbable organic halogens in seawater, comprising the steps of:
s1: collecting a seawater sample for later use;
s2: pretreating a seawater sample by adopting a mechanical-assisted oscillation adsorption method to obtain a pretreated sample; the specific operation is as follows: placing 100ml of water sample to be detected in a conical flask, adding 10-50mg of active carbon and 5ml of sodium nitrate stock solution, and placing the conical flask on a horizontal oscillator for oscillation; then adding the oscillated water sample to be detected into a Buchner funnel for suction filtration; after suction filtration, adding the sodium nitrate eluent into a Buchner funnel, mechanically stirring for 1min, and performing suction filtration for primary elution after stirring; when the liquid in the Buchner funnel is below the filter layer, adding sodium nitrate eluent to carry out secondary elution; after washing, transferring the filter membrane and the filter cake to a quartz sample tube together to obtain a sample after pretreatment;
s3: and (4) measuring the AOX value of the pretreated sample by using a microcoulometer, namely obtaining the AOX measured value.
By adopting the technical scheme, a channel effect is formed in the activated carbon filter cake formed by filter pressing, so that sodium nitrate eluent flows out of the channel in the elution process, and the eluent cannot effectively wash inorganic halide ions in the filter cake. When the traditional oscillation adsorption method is used for eluting a seawater sample, sodium nitrate eluent rapidly flows through an activated carbon filter cake under the action of a vacuum pump, so that a 'pore effect' is more easily formed, when the oscillation adsorption method is used for eluting the seawater sample, activated carbon powder is fixed in a small quartz column with a specific size, and the eluent flows through the small activated carbon column from top to bottom, so that the 'pore effect' is possibly formed. Meanwhile, because the concentration of inorganic halide ions in seawater is extremely high, the 'pore effect' is possibly amplified, namely, few residues have great influence on the measurement result, and larger accidental errors are caused.
In order to eliminate the 'pore effect', the elution mode is improved by introducing manual mechanical assistance in the suction filtration process when the vibration adsorption method is adopted for processing, the activated carbon is in a suspension state in the eluent, the contact area of the activated carbon and the eluent is enlarged, the elution effect is improved, the possibility of forming the 'pore effect' is eliminated, and the precision of a test result is good.
Preferably, the method further comprises the following steps:
s4: measuring the AOX content of the simulated blank seawater sample as an AOX correction blank value;
s5: the actual AOX value of the seawater sample is the difference between the AOX measured value and the AOX correction blank value.
By adopting the technical scheme, the improved oscillation adsorption method cannot eliminate the positive error of high-concentration inorganic halide ions in seawater on AOX measurement, but the interference of the correction blank concept on the measurement result can be effectively eliminated after the correction blank concept is introduced and subtracted.
Preferably, in step S4, the AOX calibration blank value determination step for simulating a blank seawater sample is as follows:
step 1: preparing simulated seawater stock solution, and simulating Cl in seawater stock solution-1Is 20 g.L-1，Br-1Is 100 mg.L-1，I-1Is 100. mu.g.L-1；
Step 2: preparing Cl by using simulated seawater stock solution and pure water according to different proportions-1A plurality of groups of simulated blank seawater samples with increasing concentrations;
and step 3: the AOX value of the simulated plain seawater sample was measured in the same manner as in steps S2 and S3, and measured as Cl-1Fitting the concentration and the AOX measured value of the blank seawater sample by using a horizontal coordinate and a vertical coordinate to obtain a linear correction curve and obtain a formula of the curve;
and 4, step 4: cl of the seawater sample in the step S1-1And (4) substituting the concentration into the formula in the step (3) to obtain an AOX correction blank value of the seawater sample.
By adopting the technical scheme, the AOX value is measured after the prepared simulated seawater stock solution is treated by the oscillation adsorption method in the application, and the AOX value shows that the deviation of AOX measurement in seawater without adsorbable organic halogen has correlation with the halogen ion concentration, the concentration of chloride ions in seawater is the largest, and the influence on the measurement is also fallen, so that the AOX correction blank value under each chloride ion concentration is obtained according to the linear equation of the chloride ions and the measured AOX value.
Preferably, step S1 is specifically: collecting seawater samples at different places of a region to be measured, collecting the seawater samples by using brown glass bottles, immediately adding a sodium sulfite solution and concentrated nitric acid to adjust the pH value of a water sample to be less than 2 after sampling, and preserving the samples at 1-4 ℃ for 3 days after collecting.
By adopting the technical scheme, a plurality of places are adopted for collection and testing to collect accidental errors. And the sample is collected by a brown glass bottle, adjusted by sodium sulfite solution and concentrated nitric acid, and stored and transported at low temperature, so that the sample is prevented from decomposing and losing to cause larger measurement error.
Preferably, the suction filtration speed in the pretreatment process of the seawater sample and the elution speed of the eluent are controlled to be 3-4 ml/min.
By adopting the technical scheme, the suction filtration speed and the elution speed are controlled to be 3-4ml/min, so that the phenomenon that the flow speed is too high to cause a pore effect can be avoided, but the speed is not too low to influence the efficiency.
Preferably, in step S2, the content of the eluent added in one elution is 15 ml; the content of the eluent added in the secondary elution was 10 ml.
By adopting the technical scheme, the content of the eluent in the primary eluent is more than that of the secondary eluent, so that more inorganic halogen ions are eluted by mechanical assistance in the primary elution process, and the detection accuracy is further improved.
Preferably, the concentration of the sodium nitrate stock solution is 17 g.L-1The eluent of the sodium nitrate is 0.85 g.L-1。
Preferably, the filter membrane used in the suction filtration process is a polycarbonate filter membrane.
By adopting the technical scheme, when the polycarbonate filter membrane is measured by a combustion method, impurity ions cannot be introduced to influence the detection accuracy.
In summary, the present application has the following beneficial effects:
1. the vibration adsorption method of the traditional microcoulomb method is improved, mechanical assistance is introduced during elution, the contact area of the active carbon and the eluent is enlarged, the 'pore effect' is eliminated, and the test result has good precision.
2. The improved oscillation adsorption method cannot eliminate the positive error of high-concentration inorganic halide ions in seawater on AOX measurement, but the interference of the correction blank concept on the measurement result can be effectively eliminated after the correction blank concept is introduced and subtracted.
Drawings
FIG. 1 is a graph of the chloride ion concentration of a simulated blank seawater sample as compared to the AOX blank value in example 2 of the present application.
Detailed Description
The present application will be described in further detail with reference to the following drawings and examples.
Some of the drug specifications selected in the following examples are as follows:
activated carbon (iodine value less than 1050, chlorine blank value less than 15 mug g)-1Particle size 50-150 μm), polycarbonate filter membranes (shanghai nova D25 mm; 0.45 μm), nitric acid (GR), sodium nitrate stock solution (17 g.L)-1) Sodium nitrate eluent (0.85 g.L)-1)。
Examples
Example 1
Embodiment 1 discloses a microcoulomb method for measuring adsorbable organic halogen in seawater, which specifically comprises the following steps:
s1: sampling seawater. Selecting 3 different places A, B, C in the same area to collect seawater samples, filling the water samples with brown glass bottles, immediately adding sodium sulfite solution and concentrated nitric acid after sampling, adjusting the pH value of the seawater samples to 1, and leaving no air on the brown glass bottles. After sampling, the sample is stored at 2 ℃ and transported to a laboratory, and the determination is completed within 3 days. A. B, C were measured by separate treatments of the seawater samples taken.
S2: the seawater sample is pretreated by adopting a mechanical auxiliary oscillation adsorption method. 100ml of seawater sample is added into a 250ml conical flask and then oscillated for 1h on a horizontal oscillator at the frequency of line return 150 times/min and amplitude of 6 cm; the shaken seawater sample was transferred to a Buchner funnel at 3 mL. min-1At a filter pressing speed ofCarrying out suction filtration; after the suction filtration is finished, adding 15ml of sodium nitrate eluent, mechanically stirring for 1min, and carrying out suction filtration for primary elution after stirring; when the liquid in the Buchner funnel is below the filter layer, adding 10ml of sodium nitrate eluent for secondary elution; the elution speed was also controlled at 3mL/min-1(ii) a The elution speed was also controlled at 3mL/min-1(ii) a And after elution, transferring the wet filter cake and the polycarbonate filter membrane to an oscillation quartz sample tube together to obtain a pretreated sample.
S3: and (4) measuring the AOX value of the pretreated sample by using a microcoulometer to obtain the AOX measured value of the seawater sample.
Example 2
Embodiment 2 discloses a microcoulomb method for measuring adsorbable organic halogen in seawater, which specifically comprises the following steps:
s1: sampling seawater. Selecting 3 different places A, B, C in the same area to collect seawater samples, filling the water samples with brown glass bottles, immediately adding sodium sulfite solution and concentrated nitric acid after sampling, adjusting the pH value of the seawater samples to 1, and leaving no air on the brown glass bottles. After sampling, the sample is stored at 2 ℃ and transported to a laboratory, and the determination is completed within 3 days. A. B, C were measured by separate treatments of the seawater samples taken.
S2: the seawater sample is pretreated by adopting an oscillation adsorption method.
100ml of seawater sample is added into a 250ml conical flask and then oscillated for 1h on a horizontal oscillator at the frequency of line return 150 times/min and amplitude of 6 cm; transferring the oscillated seawater sample to a Buchner funnel, and performing suction filtration at a suction filtration speed of 3 ml/min; after the suction filtration is finished, adding 15ml of sodium nitrate eluent, mechanically stirring for 1min, and carrying out suction filtration for primary elution after stirring; when the liquid in the Buchner funnel is below the filter layer, adding 10ml of sodium nitrate eluent for secondary elution; the elution speed was also controlled at 3mL/min-1(ii) a And after elution, transferring the wet filter cake and the polycarbonate filter membrane to an oscillation quartz sample tube together to obtain a pretreated sample.
S3: and (4) measuring the AOX value of the pretreated sample by using a microcoulometer to obtain the AOX measured value of the seawater sample.
S4: AOX corrected blank values were determined. The method comprises the following specific steps:
step 1: preparing simulated seawater stock solution, and simulating Cl in seawater stock solution-1Is 20 g.L-1， Br-1Is 100 mg.L-1，I-1Is 100. mu.g.L-1；
Step 2: preparing Cl by using simulated seawater stock solution and pure water according to different proportions-1Simulating blank seawater samples with the concentration of 0mg/L, 500mg/L, 1000mg/L, 5000mg/L, 10000mg/L, 15000mg/L and 20000 mg/L;
and step 3: adopting the same seawater sample pretreatment method and determination method as those in the first step to respectively determine AOX value of the simulated blank seawater sample, and using Cl-1Fitting the concentration and the AOX measured value of the blank seawater sample by using a horizontal coordinate and a vertical coordinate to obtain a linear correction curve, as shown in figure 1, and obtaining a formula (1) of the curve; the formula (1) is: y 0.00181X + 11.70.
And 4, step 4: cl of seawater sample in step (i)-1And (4) substituting the concentration into the formula in the step (3) to obtain an AOX correction blank value of the seawater sample.
Step S5: calculating the actual AOX value of the seawater sample. The calculation method is as follows:
the actual AOX value of the seawater sample is AOX measured value-AOX corrected blank value.
Comparative example
Comparative example 1
Comparative example 1 differs from example 1 in that the AOX value of the seawater sample was measured by treating the seawater sample with the oscillation method in GB/T15959-1995 microcoulomb method for measuring organic halogen adsorbable in water.
Comparative example 2
Comparative example 1 differs from example 1 in that the AOX value of the seawater sample was measured by treating the seawater sample by the two-column method in GB/T15959-1995 microcoulomb method for measuring organic halogen adsorbable in water.
Comparative example 3
Preparing Cl with the concentration of 0mg/L, 200mg/L, 400mg/L, 600mg/L, 800mg/L and 1000mg/L by using pure water-1Solution, detection of different Cl-1Blank value of AOX at concentration and in Cl-1Fitting the concentration and the AOX blank value by using horizontal and vertical coordinates to obtain a linear curve and obtaining a formula (2) of the curve; the formula (2) is: y is 0.05X + 3.46.
Data comparison analysis
1. From a comparison of formula (1) and formula (2), it can be seen that when Cl is present-1The concentration is 1000 mg.L-1Then, the blank value of AOX correction obtained by the formulas (2) and (1) was from 53.46. mu.g.L-1Reduced to 13.51. mu.g.L-1The correction blank is significantly reduced. This demonstrates that the mechanically assisted oscillatory adsorption process of the present application can effectively remove the effect of inorganic halogen ions in seawater.
2. And (4) measuring and analyzing a seawater sample.
TABLE 1 results of measuring seawater samples
And (4) conclusion: as can be seen from Table 1, when the seawater sample is measured by the two-column method, the maximum value in the parallel sample test can be more than 10 times the minimum value, and the measured values of the two small columns have no obvious rule, which does not conform to the standard method that the concentration of the column 2 is not more than 10% of the concentration of the column 1, so the measurement result obtained by the two-column method is unreliable.
Using conventional shaking methods, the relative standard deviation of the three spots is 22.8% -197%. Therefore, the current microcoulomb method is not suitable for the measurement of seawater, and firstly shows that the precision of the measurement result is poor. This is probably because the seawater is rich in inorganic halogen ions, the elution mode in the current method cannot effectively elute the inorganic halogen ions, and the residual inorganic halogen ions are converted into hydrogen halide after high-temperature combustion, which interferes the test result. In the double-column method, the seawater sample flows through two active carbon small columns which are connected in series, and the probability of inorganic halogen ions left in the active carbon is higher, so that the precision is poorer.
After the improved method is used, the relative standard deviation of the determination results of the three point positions is lower than 10%. The active carbon is in a suspension state in the eluent due to the introduction of mechanical assistance, so that the contact area of the active carbon and the eluent is enlarged, the possibility of forming a channel effect is eliminated, and the elution effect is improved; then according to a double-column method or a method of a complete set of adsorption pretreatment device, 3ml/min-1The elution rate was calculated to be about 8.3min for 25ml of eluent, and about 3min for two washes after modification. Not only saves the analysis time, but also can avoid the problem that the eluted inorganic halide ions are adsorbed by the active carbon again due to long-time contact.
3. And (3) standard adding determination analysis, wherein the method comprises the following steps: prepared according to the preparation method of the simulated blank seawater sample in the example 2 to obtain 0 mg.L-1、500mg·L-1、1000mg·L-1、5000mg·L-1、 10000mg·L-1、15000mg·L-1、20000mg·L-1Different Cl of-1And (3) simulating blank seawater samples with the concentration, adding hydroquinone into each group of the simulated blank seawater samples, and controlling the concentration of the hydroquinone in the added simulated blank seawater samples to be 50 mu g/L. The simulated blank seawater samples after addition of hydroquinone were then tested using the methods of examples 1 and 2.
TABLE 2 simulated AOX recovery in seawater
Note: the whole process blank is the whole process blank of the pure water matrix.
And (4) conclusion: as can be seen from Table 2, with simulation of Cl in seawater-1The AOX recovery rate gradually increases with increasing concentration. When Cl is present-1Up to 20 g.L-1In example 1, the recovery of AOX was as high as 175%. Therefore, the deviation of the AOX measurement caused by the inorganic halide ions in the seawater must be considered. GB/T15959-1995 Water adsorbable organicStandard methods such as microcoulomb method for halogen measurement stipulate that the AOX measurement result of an actual sample is the difference between the sample measurement value and the AOX full-process blank value, the concentration difference between seawater and freshwater halide ions is significant, and it is not appropriate to use pure water as the full-process blank when measuring seawater.
When the effect of inorganic halide ions is considered, the inorganic chlorine concentration is substituted into the formula (1) to obtain a correction blank to replace the whole process blank for the standard addition recovery calculation, Cl-1The concentration is 0-20000 mg.L-1The recovery rate of the simulated seawater within the range is 93.8-109%, the average recovery rate is 103%, and the requirement of standard method on the deviation of the recovery rate of the simulated seawater not more than 10% is met. Therefore, although the improved oscillation method cannot reduce the positive error of the AOX measurement caused by high-concentration inorganic halide ions in the seawater, the interference of the correction blank concept on the measurement result can be effectively eliminated after the correction blank concept is introduced and calculation is carried out.
The improved oscillation method can achieve good precision during AOX test of seawater, and has good accuracy, and standard recovery meets standard requirements. Although increasing the concentration and volume of the eluent theoretically improves the elution effect and reduces the interference caused by the inorganic halide ions, part of AOX is lost to cause lower recovery, so that the standard method requires that the change of the volume or concentration of the eluent needs to be clearly indicated. The method has the advantages that the concentration and the volume of the eluent are not changed in the elution process, and the comparability of the test result with the current standard method is ensured, so that the method is feasible as a method for measuring the AOX in seawater.
Method verification
1. Linear range
With reference to GB/T15959-1995 microcoulomb method for measuring organic halogen adsorbable in water, sample pretreatment was performed by modified oscillatory adsorption method, and standard sequences (AOX concentrations of 0, 10, 50, 100, 200, 300, 400. mu.g.L, respectively) were performed in a pure water matrix-1) And (4) carrying out the whole process measurement, and carrying out regression analysis on the result. The measurement result shows that the improved post-oscillation adsorption method has the AOX concentration of 0-400 mu g.L-1Good linearity within range, linear phaseThe relation number is 0.9995, the slope is 0.9749, and the requirements that the correlation coefficient is more than or equal to 0.999 and the slope range is between 0.95 and 1.05 in the standard method are met.
2. Method detection limit
The influence of the difference of the content of the halogen ions in the actual seawater on the measurement is different. The higher the halogen ion concentration, the greater the effect on the test, and the higher the detection limit of the corresponding method. Due to Cl in seawater in general-1The concentration of the solution is not more than 20 g.L-1Therefore, the direction is 20 g.L-1Cl-120 mu g.L of the simulated seawater-1(20mg·L-10.10ml) of parachlorophenol, determining the AOX value of the simulated seawater, determining in parallel for 6 times, deducting the correction blank, and calculating to obtain the detection limit of 6.49 mu g.L-1The lower limit of the measurement is 26.0. mu.g.L-1. The detection limit of the method is superior to GB/T15959-1995 (the detection limit of the method is 10 mug. L)-1) Slightly lower than EPA9020B (6.6. mu.g.L)-1)。
3. Actual seawater sample testing
According to GB17378.4-2007 marine monitoring specification part 4: the silver method in seawater analysis was used to test Cl-1 in A, B, C san Didi seawater in this experiment. The results of the oscillatory sorption-mechanical assistance/suction filtration mode AOX measurement of Table 1 were corrected according to the expression (1), and the results are shown in Table 3.
TABLE 3 actual seawater sample calibration results
Adding 50 mu g.L into A, B, C Sandi seawater-1(20mg·L-10.25ml) of p-chlorophenol, the results of the substrate spiking recovery measurements are shown in Table 4.
TABLE 4 actual sample matrix spiking recovery
The recovery rate of the actual sample by adding the standard is between 90.6 and 107 percent, and the requirement of 10 percent of deviation in the standard method is met.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (8)
1. A microcoulomb method for measuring adsorbable organic halogens in seawater, comprising the steps of:
s1: collecting a seawater sample for later use;
s2: pretreating a seawater sample by adopting a mechanical-assisted oscillation adsorption method to obtain a pretreated sample; the specific operation is as follows: placing 100ml of water sample to be detected in a conical flask, adding 10-50mg of active carbon and 5ml of sodium nitrate stock solution, and placing the conical flask on a horizontal oscillator for oscillation; then adding the oscillated water sample to be detected into a Buchner funnel for suction filtration; after suction filtration, adding the sodium nitrate eluent into a Buchner funnel, mechanically stirring for 1min, and performing suction filtration for primary elution after stirring; when the liquid in the Buchner funnel is below the filter layer, adding sodium nitrate eluent to carry out secondary elution; after washing, transferring the filter membrane and the filter cake to a quartz sample tube together to obtain a sample after pretreatment;
s3: and (4) measuring the AOX value of the pretreated sample by using a microcoulometer, namely obtaining the AOX measured value.
2. The microcoulomb method for measuring adsorbable organohalogen in seawater as claimed in claim 1, further comprising the steps of:
s4: measuring the AOX content of the simulated blank seawater sample as an AOX correction blank value;
s5: the actual AOX value of the seawater sample is the difference between the AOX measured value and the AOX correction blank value.
3. The microcoulomb method for measuring adsorbable organohalogen in seawater according to claim 2, wherein: in step S4, the measurement of AOX correction blank value of the simulated blank seawater sample comprises the following steps:
step 1: preparing simulated seawater stock solution, and simulating Cl in seawater stock solution-1Is 20 g.L-1，Br-1Is 100 mg.L-1，I-1Is 100. mu.g.L-1；
Step 2: preparing Cl by using simulated seawater stock solution and pure water according to different proportions-1A plurality of groups of simulated blank seawater samples with increasing concentrations;
and step 3: the AOX value of the simulated plain seawater sample was measured in the same manner as in steps S2 and S3, and measured as Cl-1Fitting the concentration and the AOX measured value of the blank seawater sample by using a horizontal coordinate and a vertical coordinate to obtain a linear correction curve and obtain a formula of the curve;
and 4, step 4: cl of the seawater sample in the step S1-1And (4) substituting the concentration into the formula in the step (3) to obtain an AOX correction blank value of the seawater sample.
4. The microcoulomb method for measuring adsorbable organohalogen in seawater according to claim 1, wherein: step S1 specifically includes: collecting seawater samples at different places of a region to be measured, collecting the seawater samples by using brown glass bottles, immediately adding a sodium sulfite solution and concentrated nitric acid to adjust the pH value of a water sample to be less than 2 after sampling, and preserving the samples at 1-4 ℃ for 3 days after collecting.
5. The microcoulomb method for measuring adsorbable organohalogen in seawater according to claim 1, wherein: the suction filtration speed in the pretreatment process of the seawater sample and the elution speed of the eluent are controlled to be 3-4 ml/min.
6. The microcoulomb method for measuring adsorbable organohalogen in seawater according to claim 1, wherein: in step S2, the content of the eluent added in the first elution is 15 ml; the content of the eluent added in the secondary elution was 10 ml.
7. The microcoulomb method for measuring adsorbable organohalogen in seawater according to claim 1, wherein: the concentration of the sodium nitrate stock solution is 17 g.L-1The eluent of the sodium nitrate is 0.85 g.L-1。
8. The microcoulomb method for measuring adsorbable organohalogen in seawater according to claim 1, wherein: the filter membrane adopted in the suction filtration process is a polycarbonate filter membrane.
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