CN103604883B - Method for quantitatively detecting 2, 4-dichlorophenol in water - Google Patents

Abstract

The invention relates to a method for quantitatively detecting 2, 4-dichlorophenol in water, belonging to the field of analysis and detection of a compound. The invention provides a method for detecting 2, 4-dichlorophen in water through a head space solid phase microextraction-gas chromatography. The extracting head of the solid phase microextraction has the effect of gathering volatilizing components and can detect trace 2, 4-dichlorophen in water. The method can be used as a standard method for detecting the concentration of 2, 4-dichlorophen in water, the pretreatment is simple and rapid, and only needs heating and extracting for 30 minutes, no solvent is needed, the method is safe and environment-friendly, the dosage of the sample is less, the method has good linear adding standard recovery, and the detection sensitivity can reach 6.54mu g/L.

Description

The quantitative detecting method of 2,4-chlorophenesic acids in a kind of water

Technical field

The present invention relates to the quantitative detection of 2,4-chlorophenesic acids in water, headspace solid-phase microextraction combines with gas chromatographic detection technology by the method, quantitatively detects rapidly and accurately to 2,4-Dichlorophenol, belongs to compound analysis detection field.

Background technology

2,4-Dichlorophenol (2,4-Dichlorophenol, 2,4-DCP) is a kind of poisonous persistent organic pollutants, it be by the hydrogen atom of 2,4 on phenol phenyl ring by chlorine atom replace produce.In time for many years in the past, it is by the various movable entered environment of the mankind, as waste incineration, not controlled use wood preservative, pesticide, germifuge, herbicide, and association with pulp bleaching; Meanwhile, be released in environment as solvent, lubricant and synthesis refuse.

The three-induced effect that 2,4-Dichlorophenol has " teratogenesis, carcinogenic, mutagenesis ", can accumulate in vivo, have very strong biological stability, once contaminated environment, by extended residual.It has hidden, permanent especially to the pollution of underground water and difficulty is restorative; It has stronger adsorbability to soil, changes the ecologic environment of soil, affects the home function of geobiont.2,4-Dichlorophenol has been listed in 68 kinds of priority pollutants " blacklist " and " National Hazard product register " by China, and concrete regulation has been made in the discharge of " integrated wastewater discharge standard " (GB8978-1996) also parachlorphenol.

At present, the detection method of 2,4-Dichlorophenol mainly contains spectrophotometric method, vapor-phase chromatography (GC) and high performance liquid chromatography (HPLC).Wherein spectrophotometry sensitivity is lower, complex operation; GC and HPLC method can not directly measure, and needs complicated pre-treatment, and need use a large amount of solvent, and sample loss is comparatively large, and complex operation, poor reproducibility, the recovery is low.The present invention selects solid-phase microextraction as Sample Pretreatment Technique, coupling GC(ECD detecting device) to measure in water 2,4-Dichlorophenol content, overcome above-mentioned deficiency, solid phase micro-extraction technique treasury is got, be separated, concentrate, sample introduction, there is quick, easy feature, few without the need to plus solvent, required water sample amount in integrated operation process, step simple, efficiency and highly sensitive, is applicable to the Fast Measurement of content of material.

Summary of the invention

The technical issues that need to address of the present invention are, provide a kind of with Isosorbide-5-Nitrae-dichloro-benzenes for internal standard compound quantitatively detects the GC conditions of 2,4-Dichlorophenol, and determine correlation parameter and the operation steps of pre-treatment.

The quantitative detecting method of 2,4-chlorophenesic acids in a kind of water, is characterized in that:

(1) in 20ml ml headspace bottle, inject 5ml mark-on water sample with microsampling pin, regulate pH to 6 and concentration adjustment to be 0.2g/ml, add rotor, press bottle cap with gland device immediately, shake up, to be measured;

(2) open constant temperature blender with magnetic force, temperature is set to 25 DEG C, after temperature stabilization, sample bottle is put into water bath with thermostatic control and balances 30min;

(3) loaded by extracting fiber head in extraction handle, composition manual solid-phase micro-extraction injector, is thrust the vaporizer that temperature is 260 DEG C, releases fiber head, carry out aging, remained in the impurity on fiber head by aging removal;

(4) after aging end, thrust in sample bottle by the needle tubing of solid-phase micro-extracting device, pressure handle piston, fiber head does not contact with liquid level, headspace extraction 10min;

(5) extracted rear retraction fiber head, insert Thermal desorption 3min in gas chromatograph vaporizer rapidly, after completing, retraction fiber head, extracts injector; Gas chromatograph goes out blob detection automatically;

In detection, chromatographic condition is: HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 130 DEG C, rise to 280 DEG C with 30 DEG C/min with 15 DEG C/min, keeps 2min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min;

Before detection, the chromatographic condition that fiber head is aging: HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 260 DEG C with 5 DEG C/min, keeps 30min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min.

The GC conditions of internal mark method determination 2,4-Dichlorophenol provided by the invention is, chromatographic column: adopt HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 130 DEG C, rise to 280 DEG C with 30 DEG C/min with 15 DEG C/min, keeps 2min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min.It is all better that this chromatographic condition obtains the parameters such as chromatographic peak symmetry, degree of separation.

Temperature can affect the partition equilibrium constant of compound between solid liquid phase and liquid phase, therefore needs to determine best extraction temperature.Configure certain density mark-on solution to be measured, extraction time 20min, absorption 6min, from 15 DEG C, often raise 5 DEG C is a test point, to 40 DEG C.Measurement result shows, and with the rising of temperature, the response of 2,4-Dichlorophenol increases gradually, and tends to balance after 25 DEG C, adopts 25 DEG C.

Extraction time is the important factor in order of extraction process, extraction temperature 25 DEG C, adsorption time 6min, with 10min, 20min, 30min, 40min, 50min, 60min for test point, detects same concentration mark-on solution to be measured; Result shows, along with the time lengthens, 2,4-Dichlorophenol peak area becomes large gradually, tends to balance after 30min test point.Extraction temperature 25 DEG C, extraction time 30min, with 5min, 10min, 15min, 20min for test point, the optimal adsorption time determined is 10min.Extraction temperature 25 DEG C, extraction time 30min, adsorption time 10min, with 1min, 2min, 3min, 4min for test point, under vaporizer temperature 260 DEG C of conditions, the parsing time is 3min.

Add salt (NaCl) in solution 2,4-Dichlorophenol can be suppressed to ionize and reduce its solubleness in the solution, improve gas-liquid partition coefficient, improve analysis efficiency.In 5 parts of 5ml same concentration mark-on solution to be measured, add 0 respectively, 0.5,1,1.5,2gNaCl measures, result shows, after 1g test point, peak area raises trend and tends towards stability, so, sample ions concentration value should be adjusted to 0.2g/ml.

Because 2,4-Dichlorophenol is faintly acid, reduce pH value and its ionization property can be made to reduce, improve the adsorption rate of gas-liquid partition coefficient and fiber Stationary liquid, the sensitivity of raising method, but acidity too by force also can damaged fiber Stationary liquid.Test HCl regulates same concentration mark-on sample pH value to be 2,3,4,5,6 to measure respectively, and result shows, reaches good response when pH is 6, also can not produce the fiber Stationary liquid of extracting head and damage, so, sample pH should be adjusted to 6.

Advantage of the present invention is as follows:

The first, the present invention adopts Solid-phase Microextraction, comparatively liquid-phase extraction, and required quantity of solvent is few, safety and environmental protection, and step is easy, and interfering material is few;

The second, solid phase micro-extracting head does not directly contact with sample, but head space adsorbs the determinand in gas phase, enrichment, can avoid coming off and running off of fiber coat like this, also can reduce sample matrices interference;

3rd, assay method is internal standard method, and compared with external standard method, have better accuracy and precision, the character of Isosorbide-5-Nitrae-dichloro-benzenes and 2,4-Dichlorophenol is close, and appearance time is more or less the same and does not interfere with each other.

4th, method detects and is limited to 6.54 μ g/L, and the recovery can reach 90 ~ 103%, has good sensitivity and precision.

Accompanying drawing explanation

Fig. 1 internal mark method determination working curve diagram

Figure 22,4-Dichlorophenol and Isosorbide-5-Nitrae-dichloro-benzenes standard gas chromatograph figure (go out peak when 8min, 10min and be respectively 2,4-Dichlorophenol peaks, Isosorbide-5-Nitrae-dichloro-benzenes peak)

Embodiment

This invention is explained further below by embodiment.

Embodiment 1: the selection of working curve

Compound concentration is the standard serial solution of 0mg/L, 0.1mg/L, 0.2mg/L, 0.3mg/L, 0.4mg/L, 0.5mg/L, measures according to the step in summary of the invention.With 2,4-Dichlorophenol concentration for x-axis, 2,4-Dichlorophenol and Isosorbide-5-Nitrae-dichloro-benzenes peak area ratio are y-axis, and set up the curve of the relation between the two that represents, its equation is: y=2.9737x, the R of curve ²=0.9944, well Linearity.

Embodiment 2: the mensuration of actual water sample

Before detection, first carry out aging to fiber head, aging chromatographic condition is: HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 260 DEG C with 5 DEG C/min, keeps 30min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min.After aging, chromatographic condition is set to: HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 130 DEG C, rise to 280 DEG C with 30 DEG C/min with 15 DEG C/min, keeps 2min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min.

Water sample is the water outlet of laboratory reaction device, the maximum concentration value 0.5mg/L that contained by water outlet, 2,4-Dichlorophenol concentration can detect higher than the method, therefore, dilute during preparation sample, thinned water is that Wahaha Pure Water replaces, and before application, inspected is without chromatogram Interference Peaks.In 20ml ml headspace bottle, add magnetic agitation rotor, add water sample and certain thinned water 5ml altogether, add the Isosorbide-5-Nitrae-dichloro-benzenes internal standard compound of 5 μ l100mg/L, regulate pH to 6, adjustment concentration is 0.2g/ml, immediately capping, shakes up; 30min is balanced, extraction absorption 10min in constant temperature blender with magnetic force 25 DEG C of water-baths.Thermal desorption 3min in gas chromatograph 260 DEG C of vaporizers, is finally calculated the peak area ratio at detected material peak and internal standard compound peak by chromatogram, calculate the concentration of contained 2,4-Dichlorophenol in water sample according to working curve.Reckoner is as shown below.

Claims (1)

1. the quantitative detecting method of 2,4-chlorophenesic acids in a water, is characterized in that:

(1) in 20ml ml headspace bottle, inject 5ml mark-on water sample with microsampling pin, regulate pH to 6 and concentration adjustment to be 0.2g/ml, add rotor, press bottle cap with gland device immediately, shake up, to be measured;

(2) open constant temperature blender with magnetic force, temperature is set to 25 DEG C, after temperature stabilization, sample bottle is put into water bath with thermostatic control and balances 30min;

(3) loaded by extracting fiber head in extraction handle, composition manual solid-phase micro-extraction injector, is thrust the vaporizer that temperature is 260 DEG C, releases fiber head, carry out aging, remained in the impurity on fiber head by aging removal;

(4) after aging end, thrust in sample bottle by the needle tubing of solid-phase micro-extracting device, pressure handle piston, fiber head does not contact with liquid level, headspace extraction 10min;

(5) extracted rear retraction fiber head, insert Thermal desorption 3min in gas chromatograph vaporizer rapidly, after completing, retraction fiber head, extracts injector; Gas chromatograph goes out blob detection automatically;

In detection, chromatographic condition is: HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 130 DEG C, rise to 280 DEG C with 30 DEG C/min with 15 DEG C/min, keeps 2min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min;

Before detection, the chromatographic condition that fiber head is aging: HP-5 capillary column; Vaporizer temperature is: 260 DEG C; Detector temperature: 280 DEG C; Column temperature: 60 DEG C, keeps 5min, rises to 260 DEG C with 5 DEG C/min, keeps 30min; Carrier gas is nitrogen, flow velocity: 2ml/min; Make-up gas: 60ml/min.