The Static Headspace gas phase chromatogram electron capture detection method of 11 kinds of chlorobenzene compounds in a kind of water body
Technical field
The present invention relates to Isosorbide-5-Nitrae-dichloro-benzenes, 1 in a kind of water body, 3-dichloro-benzenes, 1,2-dichloro-benzenes, 1,3,5-trichloro-benzenes, 1,2,4-trichloro-benzenes, 1,2,3-trichloro-benzenes, 1,2,3,5-tetrachlorobenzene, 1,2,4,5-tetrachlorobenzene, 1,2, the Static Headspace gas phase chromatogram electron capture detection method of 3,4-tetrachlorobenzene, pentachlorobenzene, 11 kinds of chlorobenzene compounds of hexachloro-benzene, belongs to water pollution detection technical field.
Background technology
In recent decades, chlorobenzene compound is widely used in chemical synthetic pesticide, medicine, dyestuff, plastics and other chemical products, because uncontrolled waste water discharges and industrial atmosphere discharges it is extensively distributed in water environment.Chlorobenzene compound belongs to lipophilic compound, and stable chemical nature is difficult for degraded, and long-term suction may cause liver cancer, and they are classified as priority pollutants by Environmental Protection Agency (EPA).Therefore, find chlorobenzene compound detection technique in a kind of simple, quick, highly sensitive water body and seem particularly important.
At present, the trace amounts of chlorine benzene-like compounds in water body detects main by gas chromatography electron capture method or GC-MS.Conventional pretreatment technology mainly contains liquid-liquid extraction method, solid phase extraction, liquid-phase micro-extraction method, headspace solid-phase microextraction method, headspace liquid-phase microextraction method, dispersive liquid-liquid microextraction method and microwave extraction method etc.But in above-mentioned pretreatment technology, conventionally need to use the organic solvent of micro updating or milliliter level as extractant, and operation more complicated.Find a kind of simplyr, in the water body of environmental protection, the pre-treating method of chlorobenzene compound becomes study hotspot.
Since reported first in 1958 coupling technique of Static Headspace sampling device and gas chromatograph, Static Headspace sample introduction has become the most ripe headspace sampling technology, and as the first-selected analytical technology of volatile organic matter in environmental sample, flavouring, pharmaceutical industry, clinical analysis and bioanalysis, development along with other headspace technique (dynamically head space, head space solid phase or liquid-phase micro-extraction), Static Headspace technology is simple because of it, efficiently, without organic solvent, environmental friendliness be easy to the features such as realization, remain the headspace sampling technology that the most easily realizes robotization.But limited by sensitivity, Static Headspace technology is generally used for analyzing high ppb level concentration sample or improves sensitivity by increasing sample size.Static Headspace technology is combined and can be overcome the low shortcoming of sensitivity with applicable detecting device.As everyone knows, electron capture detector has high selectivity and sensitivity to organochlorine, is to analyze in the past the important means of chlorinated organics half a century.Chlorobenzene compound contains 1 ~ 6 chlorine substituent, and except chlorobenzene is not too sensitive to electron capture detector, other 11 kinds of chlorobenzene compounds are all comparatively sensitive.But consult current domestic and foreign literature, the headspace gas chromatography hydrogen flameionization detection method of Chu Che pavilion report is measured chlorobenzene, 1 in water body, 2-dichloro-benzenes, 1,4-dichloro-benzenes, 1,2, the headspace gas chromatography electron capture detection method of the report such as 4-trichloro-benzenes and Han Changmian is measured chlorobenzene, 1,2-dichloro-benzenes, 1,3-dichloro-benzenes, 1,4-dichloro-benzenes, 1, the several pieces of documents such as 2,4-trichloro-benzenes, not yet have the report for detection of 11 kinds of chlorobenzene compounds by Static Headspace technology and the coupling of gas chromatography electron capture detection method.
Summary of the invention
Deficiency for above-mentioned present Research, the present invention analyzes present situation according to Chlorobenzens in water body, the Static Headspace gas phase chromatogram electron capture detection method of chlorobenzene compound in a kind of water body is provided, the method comprises sampling successively, Static Headspace sample introduction programming and operation, gas chromatography-electron capture detector detects, Specification Curve of Increasing, sample and determination of recovery rates.
The present invention operates in accordance with the following methods:
(1) sampling: measure appropriate water sample in head space bottle, add sodium chloride to regulate water sample salinity, use immediately head space bottle cap sealing, vortex dissolves sodium chloride, and sample is placed on head-space sampler.Concrete grammar is: measure 10.00 mL water samples in the head space bottle of 20 mL specifications, making gas-liquid volume ratio in head space bottle is 1:1, add 2.00 g sodium chloride, the aluminium lid sealing by the silicagel pad of coating tetrafluoroethylene film in band by top empty bottle mouth with head space bottle bottle sealing device immediately; With vortex oscillator vortex, dissolve sodium chloride, making to add sodium chloride concentration is 20%(v/w), sample is placed on 32 head-space samplers; Gas-liquid volume ratio and add sodium chloride concentration all to affect each component peaks area, in above-mentioned sampling procedure, sample volume is 10.00 mL, and head space bottle is 20 mL, and therefore, in head space bottle, gas-liquid volume ratio is 1:1; Sodium chloride addition is 2.00 g, i.e. sodium chloride-containing 20%(w/v in final 10.00 mL water samples), different sodium chloride concentrations affect and see accompanying drawing 1 peak area, and different gas-liquid volume ratios affect and see accompanying drawing, 2 peak area.The signal that considers 11 kinds of chlorobenzene compounds is corresponding, and from accompanying drawing 1, optimal chlorination na concn is 20%(w/v), from accompanying drawing 2, best gas-liquid volume ratio is 1:1.
(2) Static Headspace sample introduction programming and operation: according to parameters such as the Static Headspace equilibrium temperature setting, equilibration time, jolting speed, operation Static Headspace injector.Concrete grammar is: Static Headspace sampling condition is 70 ℃ of equilibrium temperatures, equilibration time 30 min, and jolting speed 500 rpm, move injector according to setting program automatically by mechanical arm; In above-mentioned Static Headspace sample introduction programming and operating procedure, the too high or too low peak area that all can affect component to be measured of equilibrium temperature, different equilibrium temperatures are shown in accompanying drawing 3 to the impact of peak area, from 3,70 ℃, accompanying drawing, are optimum balance temperature.Gas-liquid two-phase reaches balance needs certain equilibration time, different equilibration times are shown in accompanying drawing 4 to the impact of peak area, from accompanying drawing 4, along with the prolongation of equilibration time, each component peaks area increases to some extent, when equilibration time is greater than after 30 min, peak area tends towards stability, change little, in conjunction with a gas chromatographic analysis time be 28 min, for realizing continuous auto injection and determination and analysis, selected equilibration time is 30 min.
(3) gas chromatography-electron capture detector detects: sample introduction needle extracts head space bottle headspace gas, according to the gas chromatography-electron capture detector condition setting, detects.Concrete grammar is: sample introduction needle extracts head space bottle headspace gas 800 μ L, according to the gas chromatography-electron capture detector condition setting, detects; Chromatographic condition is: 220 ℃ of injector temperatures; 300 ℃ of electron capture detector temperature; Carrier gas is high pure nitrogen, and flow velocity is 1 mL/min; Sampling volume is 800 μ L; DB-35 capillary gas chromatographic column heating schedule is: 40 ℃ keep 4 min, and 10 ℃/min is warming up to 160 ℃, keep 1 min, and 10 ℃/min is warming up to 220 ℃, keep 5 min.DB-35 capillary gas chromatographic column (30 mm * 0.25, m * 0.25 μ m), fixedly phase composition is 35% diphenyl, 65% dimethyl polysiloxane can be realized effective separation of 11 kinds of chlorobenzene compounds.
(4) Specification Curve of Increasing: when water sample to be measured does not exist matrix effect, qualitative with retention time, external standard method quantitative measurement, when water sample to be measured exists matrix effect, qualitative with retention time, standard addition method quantitative measurement.External standard method concrete grammar is: get respectively appropriate chlorobenzene compound standard reserving solution, with redistilled water, be settled to 10.00 mL, obtaining 6 mark-on concentration ranges is dichloro-benzenes 0.16 ~ 8.0 μ g/L, trichloro-benzenes 0.0176 ~ 0.88 μ g/L, tetrachlorobenzene 0.004 ~ 0.2 μ g/L, pentachlorobenzene, hexachloro-benzene are the standard operation liquid of 0.001 ~ 0.05 μ g/L, requirement according to above-mentioned (1), (2), (3) step operates, according to the corresponding relation Criterion curve of the chlorobenzene compound concentration adding and peak area.Standard addition method concrete grammar is: get respectively appropriate chlorobenzene compound standard reserving solution, with water sample to be measured, be settled to 10.00 mL, obtaining 6 mark-on concentration ranges is dichloro-benzenes 0.16 ~ 8.0 μ g/L, trichloro-benzenes 0.0176 ~ 0.88 μ g/L, tetrachlorobenzene 0.004 ~ 0.2 μ g/L, pentachlorobenzene, hexachloro-benzene are the standard operation liquid of 0.001 ~ 0.05 μ g/L, requirement according to above-mentioned (1), (2), (3) step operates, according to the corresponding relation Criterion curve of the chlorobenzene compound concentration adding and peak area.Table 1 is while adopting external standard method quantitative measurement, the range of linearity of this method, related coefficient and detection limit.As shown in Table 1, each chlorobenzene compound, in the corresponding range of linearity, has good linear relationship, meets analytical approach requirement.
(5) sample and determination of recovery rates: gather water sample to be measured, requirement according to above-mentioned (1), (2), (3) step operates, and with the typical curve comparison that above-mentioned (4) step obtains, by converting, finally obtain the content of 11 kinds of chlorobenzene compounds in water sample to be measured.Adopt identical water sample, by certain addition, add standard solution (chlorobenzene compound adds scalar in Table 2), requirement according to above-mentioned (1), (2), (3) step operates, and the typical curve comparison obtaining with above-mentioned (4) step, by converting, finally obtain the content of 11 kinds of chlorobenzene compounds in mark-on water sample, carry out according to the following formula recovery calculating:
R represents the recovery, %;
C
srepresent the content of 11 kinds of chlorobenzene compounds in mark-on water sample, μ g/L;
C
0representative does not add the content of 11 kinds of chlorobenzene compounds in target water sample, μ g/L;
C represents the scalar that adds of chlorobenzene rate compound.
Heartily in pure water, laboratory tap water, Zhoushan sea area seawater, 11 kinds of chlorobenzene compound content are and do not detect.The recovery testu that the middle difference of different water bodys (Wahaha Pure Water, laboratory tap water, Zhoushan sea area seawater) adds scalar the results are shown in Table 2.The gas chromatogram of Zhoushan sea area seawater and mark-on Zhoushan sea area sea chlorobenzene compounds in water is shown in respectively accompanying drawing 5(a) and (b).
Beneficial effect of the present invention: the present invention adopts Static Headspace gas phase chromatogram electron capture detection method to measure the chlorobenzene compound in water body, the method is simple to operate, without sample pretreatment, without with an organic solvent, automaticity is high, and result is accurate, 11 kinds of chlorobenzene compounds detect and are limited to 0.0002 ~ 0.04 μ g/L, the recovery is 83 ~ 116%, has higher sensitivity and the recovery, can be for the assay of water body chlorobenzene compound.
The range of linearity of table 1 this method, related coefficient and detection limit
The recovery of table 2 different substrates water body and Precision Experiment result.
A. external standard method
B. standard addition method
Instrument and equipment used in the present invention mainly contains the CP3380 gas chromatograph (configuration electron capture detector) of U.S. Varian company production and the Combi PAL Headspace Gas Chromatography automatic sampler that Switzerland CTC Analysis AG company produces.
Accompanying drawing explanation
Accompanying drawing 1: the impact of different sodium chloride concentrations on peak area,
Accompanying drawing 2: the impact of different gas-liquid volume ratios on peak area,
Accompanying drawing 3: the impact of different equilibrium temperatures on peak area,
Accompanying drawing 4: the impact of different equilibration times on peak area,
Accompanying drawing 5: the gas chromatogram of Zhoushan sea area seawater and mark-on Zhoushan sea area sea chlorobenzene compounds in water.
Embodiment
Below in conjunction with specific embodiment, the present invention is described further, but protection scope of the present invention is not limited in this:
Embodiment 1: the mensuration of 11 kinds of chlorobenzene compounds in Wahaha Pure Water
(1) sampling: the 10.00 mL mark-on Wahaha Pure Waters (chlorobenzene compound content is in Table 2) that measure 10.00 mL Wahaha Pure Waters or contain a certain amount of chlorobenzene compound are in the head space bottle of 20 mL specifications, making gas-liquid volume ratio in head space bottle is 1:1, add 2.00 g sodium chloride, the aluminium lid sealing by the silicagel pad of coating tetrafluoroethylene film in band by top empty bottle mouth with head space bottle bottle sealing device immediately; With vortex oscillator vortex, dissolve sodium chloride, making to add sodium chloride concentration is 20%(v/w), sample is placed on 32 head-space samplers.
(2) Static Headspace sample introduction programming and operation: Static Headspace sampling condition is 70 ℃ of equilibrium temperatures, equilibration time 30 min, jolting speed 500 rpm.According to setting program, by mechanical arm, automatically move injector.
(3) gas chromatography-electron capture detector detects: sample introduction needle extracts head space bottle headspace gas 800 μ L, according to the gas chromatography-electron capture detector condition setting, detects, and qualitative with retention time, external standard method is quantitative.Chromatographic condition is: 220 ℃ of injector temperatures; 300 ℃ of electron capture detector temperature; Carrier gas is high pure nitrogen, and flow velocity is 1 mL/min; Sampling volume is 800 μ L; DB-35 capillary gas chromatographic column heating schedule is: 40 ℃ keep 4 min, and 10 ℃/min is warming up to 160 ℃, keep 1 min, and 10 ℃/min is warming up to 220 ℃, keep 5 min.
(4) external standard method drawing standard curve: get respectively appropriate chlorobenzene compound standard reserving solution, with redistilled water, be settled to 10.00 mL, obtaining 6 mark-on concentration ranges is dichloro-benzenes 0.16 ~ 8.0 μ g/L, trichloro-benzenes 0.0176 ~ 0.88 μ g/L, tetrachlorobenzene 0.004 ~ 0.2 μ g/L, pentachlorobenzene, hexachloro-benzene are the standard operation liquid of 0.001 ~ 0.05 μ g/L, requirement according to above-mentioned (1), (2), (3) step operates, according to the corresponding relation Criterion curve of the chlorobenzene compound concentration adding and peak area.
(5) sample and determination of recovery rates: adopt (4) described external standard method, record in Wahaha Pure Water 11 kinds of Chlorobenzens content and be and do not detect; In Table 2, the mark-on Wahaha Pure Water recovery is 83% ~ 116%, meets the requirement of analytical approach to the recovery.
Embodiment 2: the mensuration of 11 kinds of chlorobenzene compounds in the tap water of laboratory
(1) sampling: the 10.00 mL mark-on laboratory tap water (chlorobenzene compound content is in Table 2) that measure 10.00 mL laboratory tap water or contain a certain amount of chlorobenzene compound are in the head space bottle of 20 mL specifications, making gas-liquid volume ratio in head space bottle is 1:1, add 2.00 g sodium chloride, the aluminium lid sealing by the silicagel pad of coating tetrafluoroethylene film in band by top empty bottle mouth with head space bottle bottle sealing device immediately; With vortex oscillator vortex, dissolve sodium chloride, making to add sodium chloride concentration is 20%(v/w), sample is placed on 32 head-space samplers.
(2) Static Headspace sample introduction programming and operation: Static Headspace sampling condition is 70 ℃ of equilibrium temperatures, equilibration time 30 min, jolting speed 500 rpm.According to setting program, by mechanical arm, automatically move injector.
(3) gas chromatography-electron capture detector detects: sample introduction needle extracts head space bottle headspace gas 800 μ L, according to the gas chromatography-electron capture detector condition setting, detects, and qualitative with retention time, external standard method is quantitative.Chromatographic condition is: 220 ℃ of injector temperatures; 300 ℃ of electron capture detector temperature; Carrier gas is high pure nitrogen, and flow velocity is 1 mL/min; Sampling volume is 800 μ L; DB-35 capillary gas chromatographic column heating schedule is: 40 ℃ keep 4 min, and 10 ℃/min is warming up to 160 ℃, keep 1 min, and 10 ℃/min is warming up to 220 ℃, keep 5 min.
(4) external standard method drawing standard curve: get respectively appropriate chlorobenzene compound standard reserving solution, with redistilled water, be settled to 10.00 mL, obtaining 6 mark-on concentration ranges is dichloro-benzenes 0.16 ~ 8.0 μ g/L, trichloro-benzenes 0.0176 ~ 0.88 μ g/L, tetrachlorobenzene 0.004 ~ 0.2 μ g/L, pentachlorobenzene, hexachloro-benzene are the standard operation liquid of 0.001 ~ 0.05 μ g/L, requirement according to above-mentioned (1), (2), (3) step operates, according to the corresponding relation Criterion curve of the chlorobenzene compound concentration adding and peak area.
(5) sample and determination of recovery rates: adopt (4) described external standard method, record in the tap water of laboratory 11 kinds of Chlorobenzens content and be and do not detect; In Table 2, the mark-on laboratory tap water recovery is 89% ~ 108%, meets the requirement of analytical approach to the recovery.
Embodiment 3: the mensuration of 11 kinds of chlorobenzene compounds in Zhoushan sea area seawater
(1) sampling: the 10.00 mL mark-on Zhoushan sea area seawater (chlorobenzene compound content is in Table 2) that measure 10.00 mL Zhoushan sea area seawater or contain a certain amount of chlorobenzene compound are in the head space bottle of 20 mL specifications, making gas-liquid volume ratio in head space bottle is 1:1, add 2.00 g sodium chloride, the aluminium lid sealing by the silicagel pad of coating tetrafluoroethylene film in band by top empty bottle mouth with head space bottle bottle sealing device immediately; With vortex oscillator vortex, dissolve sodium chloride, making to add sodium chloride concentration is 20%(v/w), sample is placed on 32 head-space samplers.
(2) Static Headspace sample introduction programming and operation: Static Headspace sampling condition is 70 ℃ of equilibrium temperatures, equilibration time 30 min, jolting speed 500 rpm.According to setting program, by mechanical arm, automatically move injector.
(3) gas chromatography-electron capture detector detects: sample introduction needle extracts head space bottle headspace gas 800 μ L, according to the gas chromatography-electron capture detector condition setting, detects, and qualitative with retention time, external standard method is quantitative.Chromatographic condition is: 220 ℃ of injector temperatures; 300 ℃ of electron capture detector temperature; Carrier gas is high pure nitrogen, and flow velocity is 1 mL/min; Sampling volume is 800 μ L; DB-35 capillary gas chromatographic column heating schedule is: 40 ℃ keep 4 min, and 10 ℃/min is warming up to 160 ℃, keep 1 min, and 10 ℃/min is warming up to 220 ℃, keep 5 min.
(4) external standard method drawing standard curve: get respectively appropriate chlorobenzene compound standard reserving solution, with redistilled water, be settled to 10.00 mL, obtaining 6 mark-on concentration ranges is dichloro-benzenes 0.16 ~ 8.0 μ g/L, trichloro-benzenes 0.0176 ~ 0.88 μ g/L, tetrachlorobenzene 0.004 ~ 0.2 μ g/L, pentachlorobenzene, hexachloro-benzene are the standard operation liquid of 0.001 ~ 0.05 μ g/L, requirement according to above-mentioned (1), (2), (3) step operates, according to the corresponding relation Criterion curve of the chlorobenzene compound concentration adding and peak area.
(5) sample and determination of recovery rates: adopt (4) described external standard method, record in Zhoushan sea area seawater 11 kinds of Chlorobenzens content and be and do not detect; In Table 2, the mark-on Zhoushan sea area seawater recovery is 115% ~ 136%, and the recovery is higher, and this may be because have certain salinity (3.5%) in seawater, therefore must consider matrix effect, can consider to eliminate this matrix effect by standard addition method; The gas chromatogram of Zhoushan sea area seawater and mark-on Zhoushan sea area seawater is shown in respectively accompanying drawing 5(a) and (b).
(6) standard addition method drawing standard curve: get respectively appropriate chlorobenzene compound standard reserving solution, with Zhoushan sea area seawater, be settled to 10.00 mL, obtaining 6 mark-on concentration ranges is dichloro-benzenes 0.16 ~ 8.0 μ g/L, trichloro-benzenes 0.0176 ~ 0.88 μ g/L, tetrachlorobenzene 0.004 ~ 0.2 μ g/L, pentachlorobenzene, hexachloro-benzene are the standard operation liquid of 0.001 ~ 0.05 μ g/L, requirement according to above-mentioned (1), (2), (3) step operates, according to the corresponding relation Criterion curve of the chlorobenzene compound concentration adding and peak area.
(7) sample and determination of recovery rates: adopt (6) described standard addition method, record in Zhoushan sea area seawater 11 kinds of Chlorobenzens content and be and do not detect; In Table 2, the mark-on Zhoushan sea area seawater recovery is 93% ~ 112%, meets the requirement of analytical approach to the recovery.