CN102721766A - Application of solid phase microextraction in content analysis of naphthalene in Corex furnace gas - Google Patents

Abstract

The invention relates to solid phase microextraction, particularly an application of the solid phase microextraction in content analysis of naphthalene in Corex furnace gas. The invention is characterized by inserting an extraction head of solid phase extraction capillary fibers in a sampling bottle, extracting naphthalene in the concentrated gas, and then carrying out sample injection analysis on the fibers in a gas phase gas phase analyzer. According to the invention, the acquisition process of naphthalene in gas is greatly simplified; by adopting the solid phase microextraction technique, the sensitivity of the analysis is greatly raised; the advantages of simpleness, fast analysis, good correctness, no toxicological harmless, no pollution and the like are achieved; and the process can be prevented from being influenced by water vapour and other impurities in gas simultaneously.

Description

The SPME method is the application in the naphthalene content analysis in the Corex producer gas

Technical field

The present invention relates to the SPME method, relate in particular to the SPME method how the application in the content analysis.

Background technology

In metallurgical production; Often contain a certain amount of naphthalene in the accessory substance blast furnace gas of coal coking, especially the content of naphthalene is bigger in the Corex producer gas of Corex technology generation, and chance temperature cold season is lower; Naphthalene will condense into solid attached to inner-walls of duct or except that in the naphthalene equipment; Gas flow is reduced, cause pipeline and equipment to stop up when seriously understanding, the normal operation that influence is produced.In daily production and technological transformation, the detection of naphthalene content is extremely important in the coal gas.

At present, the naphthalene content assay method in the coal gas has " naphthalene content is measured vapor-phase chromatography (GB/T12209.2-1990) in the gas " and " naphthalene content is measured picric acid method (GB 12209.1) in the gas ".The former is applicable to that naphthalene content is at 5mg/m ³Above gas, the latter is applicable to the gas of naphthalene content more than 10mg/m3.These 2 methods all adopt absorption liquid to gather the naphthalene in the coal gas, all exist sampling time long (minimum 16h), precision low, detect the shortcomings such as influence that limit for height, poor reproducibility, sampling are subject to water vapor in the coal gas.

SPME (SPME) be grow up nineteen nineties fast, sensitive, conveniently be applicable to the sample preparation technology of the novelty of gas and fluid sample.The SPME operation steps is simple: the first step, the extracting head that scribbles stationary phase is inserted in the sample, and make determinand partition equilibrium in stationary phase coating and sample; Second step, extracting head is inserted other analytical instrument injection ports, behind the determinand desorption, can separate and detection by quantitative.SPME combines extraction, desorption, the sample introduction of determinand dexterously, just obtains fast development once coming out, and gets into the every field of analytical chemistry.At present there are not document and patent report that the SPME technology is applied in the analyzing and testing of naphthalene in the coal gas as yet.

Summary of the invention

The present invention is intended to address the above problem, and the application in the naphthalene content analysis in the Corex producer gas of a kind of SPME method is provided.The present invention has greatly simplified the naphthalene gatherer process in the coal gas; Owing to adopt solid phase micro-extraction technique greatly to improve sensitivity for analysis; Have simple, analyze fast, accuracy good, nonhazardous, advantage such as pollution-free, can not receive in the coal gas impurity effects such as water vapour simultaneously.

For addressing the above problem, the present invention proposes the application in the naphthalene content analysis in the Corex producer gas of SPME method.The present invention inserts the extracting head of SPE capillary fiber in the sampling bottle, and extraction concentrates the naphthalene in the coal gas, then this fiber is analyzed at the gas phase analyzer sample introduction, and concrete steps are following:

Step 1 is gathered the coal gas in the coal gas main line with special sampling bottle, clean volume and be the sampling bottle volume more than 40 times with the interior residual air of abundant removals bottle;

Step 2, analytic sample as early as possible after the sampling is placed on sampling bottle on the magnetic stirring apparatus, inserts the sampling bottleneck to the SPME extracting head, opens magnetic stirring apparatus, rotating speed 800r/min, balance 5min;

Step 3 is inserted the GC injection port in 240 ℃～260 ℃ with extracting head, and sample introduction behind the thermal desorption 3min is through GC peak area qualitative and quantitative analysis;

Step 4 is drawn the typical curve of each component according to the calibrating gas gained peak area of variable concentrations naphthalene;

Step 5 extracts the mensuration with GC to the coal gas sample under above-mentioned the same terms, utilize the peak area that obtains component, calculates the content of each component in sample according to typical curve.

The present invention has following characteristics:

(1) simple to operate, quick: the naphthalene that adopts the present invention to detect in the coal gas has greatly been simplified sampling process and shortened analysis time, and is easy and simple to handle, quick, is convenient to realize field quick detection, and single sample is approximately 20min whole analysis times;

(2) greatly widened the method range of application, improved sensitivity for analysis and accuracy: detecting of naphthalene is limited to 5mg/m in the existing standard coal gas ³, and the present invention can reach 0.008mg/m ³Below, and the range of linearity is wide, can be widely used in the coal gas particularly naphthalene content monitoring in the Corex producer gas, is with a wide range of applications.

(3) with low cost: extracting head can repeated application more than 1000 times.

(4) pollution-free: avoid the use of a large amount of poisonous and harmful reagent, free from environmental pollution healthy with the harm operating personnel.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed description:

Fig. 1 is an analytical equipment synoptic diagram of the present invention;

Fig. 2 influences synoptic diagram for the extraction time to effect of extracting;

Fig. 3 influences synoptic diagram for temperature to effect of extracting;

Fig. 4 influences synoptic diagram for rotating speed to effect of extracting;

Fig. 5 influences synoptic diagram for desorption time to effect of extracting.

Embodiment

The present invention proposes the application in the naphthalene content analysis in the Corex producer gas of SPME method.

The present invention inserts the extracting head of SPE capillary fiber in the sampling bottle, and extraction concentrates the naphthalene in the coal gas, then this fiber is analyzed at the gas phase analyzer sample introduction, and Fig. 1 is an analytical equipment, and wherein 1 is expansion link; 2 is handle; 3 is spring; 4 is the stainless steel needle tubing; 5 are band pellosil sealing-plug; 6 is extracting head; 7 is stirrer; 8 is magnetic stirring apparatus; 9 is air intake opening; 10 is the gas outlet.

Concrete steps are following:

Instrument and operating conditions

Instrument: solid-phase micro-extracting device: SPME hand sampling device (Supelco company), 100 μ m dimethyl silicone polymer (PDMS) extracting head (Supelco company); Heat collecting type constant temperature blender with magnetic force (Corning; PC-420d), self-control 40ml top has the sample bottle of port lid and the silica gel dottle pin of band polytetrafluoroethylene floor.

Analytical instrument: GC gas chromatograph (U.S. Agelient company), be furnished with fid detector.

Chromatographic column: quartz capillary column (Agilent19091J-413, U.S. Agelient company)

Instrumentation condition: detector temperature: 280 ℃; Injector temperature: 260 ℃; The post heating schedule:

80 ℃, stop 2min; 25 ℃/min is warming up to 200 ℃, stops 1min; 35 ℃/min is warming up to 270 ℃, stops 1min; Carrier gas is a high pure nitrogen.

Reagent and experimental technique

Analytical reagent

Naphthalene (chromatographically pure), acetone (analyzing pure)

Experimental technique

The preparation of naphthalene standard solution

With commercially available naphthalene (chromatographic grade) according to the naphthalene quality: the ratio of organic solvent-acetone volume=1g:1L is dissolved in naphthalene (GC level) standard solution of the naphthalene that is mixed with 1g/L in the acetone.

The preparation of naphthalene calibrating gas

Inject corresponding mark liquid measure according to typical curve gradient needs,, open magnetic stirring apparatus fast and transfer to 800r/min, make naphthalene calibrating gas even diffused in sample bottle the mark liquid injection sample bottle of naphthalene.

Typical curve is drawn

Draw the typical curve of each component according to the calibrating gas gained peak area of variable concentrations naphthalene, with reference to sensing range in the national standard " naphthalene content is measured vapor-phase chromatography (GB/T12209.2-1990) in the gas ".

Analytical approach to the naphthalene in the coal gas

Gather the coal gas in the coal gas main line with special sampling bottle, clean volume and be the sampling bottle volume more than 40 times with the interior residual air of abundant removals bottle.

Analytic sample as early as possible after the sampling is placed on sampling bottle on the magnetic stirring apparatus, inserts the sampling bottleneck to the SPME extracting head, opens magnetic stirring apparatus, rotating speed 800r/min, balance 5min.

Extracting head is inserted the GC injection port in 240 ℃～260 ℃, and sample introduction behind the thermal desorption 3min is through GC peak area qualitative and quantitative analysis.

Draw the typical curve of each component according to the calibrating gas gained peak area of variable concentrations naphthalene.

Under above-mentioned the same terms, the coal gas sample is extracted the mensuration with GC, utilize the peak area that obtains component, calculate the content of each component in sample according to typical curve.

Optimization of experimental conditions

The optimization of extraction time

Like Fig. 2, be rotating speed 300rpm at extraction conditions, 75 ℃ of temperature of heating plate during injection port desorption time 3min, are investigated the influence of extraction time to relative extraction quantity (peak area).As can beappreciated from fig. 2; Under the same conditions; The extraction time is to be Best Times about 15min; But be about 11min analytical approach working time of taking all factors into consideration the chromatogram naphthalene, and SPME can satisfy the sensitivity for analysis requirement of chromatograph to naphthalene to the extraction quantity of naphthalene during 5min, so the optimization extraction time of naphthalene is 5min.

The optimization of temperature

Fig. 3 is to be rotating speed 300rpm at the magnetic agitation rotating speed, extraction time 5min, and under the condition of injection port desorption time 3min, different temperatures is to the influence of relative extraction quantity.Can find out by this figure, descend after relatively extraction quantity rises to 40 ℃ with temperature of heating plate, explain that thermodynamics gets the upper hand after temperature of heating plate reaches 40 ℃ the influence of naphthalene.Owing to be heating plate heating sampling bottle, exist heating inhomogeneous, the shortcoming of temperature in the difficult control sampling bottle, and under room temperature (20 ℃), can satisfy the analysis precision requirement, take all factors into consideration the final room temperature of selecting in back as optimizing temperature.

The optimization of rotating speed

Fig. 4 is 75 ℃ of temperature of heating plate, extraction time 5min, and under the condition of injection port desorption time 3min, different rotating speeds is to the influence of relative extraction quantity.Extraction quantity improves along with rotating speed and raises relatively, reaches maximum extraction efficient at 800rpm, so select the rotating speed of 800rpm as magnetic stirring apparatus.

The optimization of desorption time

Fig. 5 is at magnetic stirring apparatus rotating speed 300rpm, 75 ℃ of temperature of heating plate, the extraction time 5min, condition under, different injection port desorption times are to the influence of relative extraction quantity.Desorption time is to relative extraction quantity influence and little, and peak area reaches maximum when desorption time is 3min, so select the rotating speed of 3min as magnetic stirring apparatus.

Method validation: detection limit, precision and the range of linearity

Method confirms that condition is: rotating speed 800rpm, room temperature, extraction time 5min, desorption time 3min.From 0.25 to 200mg/m ³, disposing the range of linearity of a series of concentration with investigation method, the typical curve recovery coefficient is 0.9998, curve a=21.12, b=-6.26 detects and is limited to 0.008mg/m ³Method detection limit and precision are as shown in table 1.

Table 1 method detection limit and precision

Claims (2)

1. SPME method is the application in the naphthalene content analysis in the Corex producer gas.

2. SPME method according to claim 1 is the application in the naphthalene content analysis in the Corex producer gas, it is characterized in that it comprises:

Step 1 is gathered the coal gas in the coal gas main line with special sampling bottle, clean volume and be the sampling bottle volume more than 40 times with the interior residual air of abundant removals bottle;

Step 2, analytic sample as early as possible after the sampling is placed on sampling bottle on the magnetic stirring apparatus, inserts the sampling bottleneck to the SPME extracting head, opens magnetic stirring apparatus, rotating speed 800r/min, balance 5min;

Step 3 is inserted the GC injection port in 240 ℃～260 ℃ with extracting head, and sample introduction behind the thermal desorption 3min is through GC peak area qualitative and quantitative analysis;

Step 4 is drawn the typical curve of each component according to the calibrating gas gained peak area of variable concentrations naphthalene;

Step 5 extracts the mensuration with GC to the coal gas sample under above-mentioned the same terms, utilize the peak area that obtains component, calculates the content of each component in sample according to typical curve.

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