CN102262163B - Rapid and automatic determination method and device for tripolycyanamide content in dairy products - Google Patents
Rapid and automatic determination method and device for tripolycyanamide content in dairy products Download PDFInfo
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Abstract
The invention discloses a rapid and automatic determination method and device for tripolycyanamide content in dairy products, belonging to the field of food analysis. The method comprises the following steps that: in a unit (A) under an operating procedure, a first step, a multifunctional valve is in a state I, a pump A rotates, a pump B stops, a first sample flows into a column 2 for enriching tripolycyanamide, and the eluent flows into a column 1 for regenerating tripolycyanamide; a second step, the pump A stops, the pump B rotates, the cleanout fluid flows into the column 2 for cleaning the impurities therein; a third step, the multifunctional valve is switched to a state II, eluent flows into the column 2 for eluting and regenerating tripolycyanamide; the tripolycyanamide in the column 2 is substituted by the eluent and directly enters into a sampling ring of a unit (B) in the form of a sample plug, so as to perform volume quantification, injection, re-separation and detection, and a response signal is processed by a computer; and meanwhile, a second sample enters into the column 1 for enrichment, and the process of the column 2 is repeated. The method and the device are high in automation degree and excellent in reproducibility, and can analyze about 30 samples per hour; and the unit (A) in the invention can be used with various flow injection analysis systems.
Description
Technical field
The present invention relates to method and the device of content of melamine quick automatic determining in the dairy products, belong to the food analysis field.The present invention can also with the coupling of multiple Flow Injection Analysis system, be used for various dairy products content of melamine fast, accurately, measure automatically.
Background technology
Melamine is the tasteless azacyclo-organic compound of a kind of white, its nitrogen content is 66.7%, be about 4 times of protein, because detection method-Kjeldahl (J. Dairy Sci. of protein in the present dairy products, 1978,61 (7): 870-873) can't distinguish proteinic nitrogen and nonprotein nitrogen, so some illegal businessman add dairy products into to improve the apparent protein content of dairy products with melamine.Melamine is understood progressively hydrolysis after entering human body, generates cyanuric acid, and melamine is combined with cyanuric acid and is formed melamine cyanurate, thereby causes calculi in urinary system, endangers healthy.Occur in U.S.'s " pet food event " (WHO Expert Meeting Report in April, 2007,2008), and " melamine milk event " (WHO Expert Meeting Report, 2008) that occur in China in September, 2008 are exactly to be caused because illegally added melamine in the food.Therefore, present fast monitored to content of melamine in the dairy products just has very great social significance.
The assay method of melamine in the dairy products, mainly contain high performance liquid chromatography (J. Agr. Food Chem., 2000,48 (8): 3353-3358), liquid chromatography-mass spectrography (Anal. Chim. Acta, 2005,530 (2): 237-243), gas chromatography-mass spectrography (Biomed. Environ. Sci., 2009,22 (2): 87-94), capillary electrophoresis (J. Agr. Food Chem., 2009,57 (3): 807-811), infra-red sepectrometry (J. Agr. Food Chem., 2009,57 (10): 3974-3980), nuclear magnetic resonance spectrometry (J. Agr. Food Chem., 2009,57 (16): 7194-7199) etc.
Liquid phase chromatography is present method used in everyday, and its sensitivity is higher, and minimum detectability is at 0.05-2.0 mg L
-1Scope, but its analysis cost height, sample pretreatment process complexity and poor reproducibility, and per hour only can analyze 2 ~ 3 samples; The capillary electrophoresis analysis cost is low, environmental protection, and minimum detectability is 0.5 mg L
-1, but its analysis speed is also very slow, per hour only can analyze two samples; The analysis speed of near infrared spectroscopy and nuclear magnetic resonance spectrometry increases, and per hour can handle 4 ~ 5 samples, but its sensitivity is low, and minimum detectability is 1 mg L
-1
The key issue of restriction said method analysis speed is, The pretreatment process and testing process are independently carried out respectively by manual, and operating process is loaded down with trivial details, and automaticity is low, can't be applicable to rapid screening and the analysis of dairy products sample in enormous quantities.
2008, three kinds of assay methods (GB/T 22388-2008) that China has issued raw milk, dairy products and contained melamine in the dairy products, that is, and high performance liquid chromatography, liquid chromatography-mass spectrography/mass spectroscopy and GC-MS(gas chromatography-mass spectrography).Three kinds of methods are except the detecting device difference of coupling, and The pretreatment and mensuration process are identical substantially.Sample pretreatment and measurement operation process that three kinds of methods are concrete are as follows: behind the samples of latex protein precipitation, get its supernatant 5 mL, adding 5 mL water mixes, allow this mixed liquor spontaneous current cross a mixed type cation exchange solid-phase extraction column, liquid to be mixed is used 3 mL water and 3 mL washed with methanol extraction columns after all flowing out again successively; After the cleaning liquid in the extraction column flows out fully, use again 6 mL ammonification methanol solutions (5.0%, v/v) wash-out; Eluent dries up with nitrogen under 50 ℃, and residue (being equivalent to 0.4 g sample) is with the mobile phase constant volume of 1 mL liquid chromatography, and vortex mixed 1 min behind the filtering with microporous membrane, is used for liquid chromatographic detection.Detecting of liquid phase chromatography is limited to 2 mg L
-1, relative standard deviation is less than 10%.When detecting with gas chromatography-mass spectrography, nitrogen dries up the residue that obtains need carry out earlier measuring behind the derivatization again.Its operating process dries up residue for getting nitrogen, adds pyridine and the 200 μ L derivatization reagents of 600 μ L, mixing, and behind 70 ℃ of reaction 30 min, air feed phase chromatography mass spectrometry detects; Detecting of gas chromatography-mass spectrography is limited to 0.05 mg L
-1, relative standard deviation is less than 10%.
There is following shortcoming in said method: 1). and sample pretreatment process and testing process are by manual operations, its process is loaded down with trivial details, automaticity is low, and personal error is big, poor reproducibility (RSD＜10%), automaticity is low, can not be applicable to the express-analysis of a large amount of samples; 2). the organic reagent consumption is big in the cleaning of mixed type cation exchange solid-phase extraction column and the elution process, and not only the hazard analysis worker's is healthy, has also increased environmental pollution simultaneously; 3). sample pretreatment process and testing process length consuming time, analysis speed is slow, is 2 ~ 3 samples/h only, is not suitable for the express-analysis of dairy products sample in enormous quantities; 4). the eluent that flows out extraction column can't directly be measured, dissolving again after needing to handle through oven dry earlier, this not only causes organic solvent volatilization contaminated environment, has also increased the pre-treatment time of sample simultaneously, has influenced whole analysis speed; 5). solid-phase extraction column is disposable use, this has not only increased considerably cost of determination (extraction column price: 10-15 unit /), waste disposal cost and the wasting of resources, and increased the source of error of pre-treatment, finally influenced accuracy and the precision of analytical approach; 6). the flow direction of example enrichment and sample wash-out can only be same direction, and eluent stream was increased through the time of extraction column, wash-out melamine, and concentrated melamine is diluted again, finally causes ion-exchanging efficiency to reduce, measure sensitivity and reduces.
In addition, United States Patent (USP) (US 2011/0008809 A1) discloses the method for melamine in a kind of enzymatic spectrophotometry food.The core of method is to utilize melamine deaminase (melamine deaminase, MDA) the catalytic trimerization cyanamide is decomposed into ammeline and ammonia, the ammonia that discharges is measured with the Berthelot chromogenic reaction, according to the melamine in the indirectly quantitative sample of the depth of color.Its specific operation process is: the dairy products supernatant 30mL that gets behind the protein precipitation flows through the cation exchange solid-phase extraction column, use 2 mL acetonitriles and 0.5% (v/v) glacial acetic acid mixed liquor, 2 mL 0.5% (v/v) glacial acetic acids, 2mL methyl alcohol to clean successively more successively, with the methanol solution (0.09 g/mL) of 0.6 mL Na-MOPS and 0.6 mL methyl alcohol wash-out successively, eluent oven dry back surplus materials is with the dissolving of 0.6mL ultrapure water, as liquid to be measured; Get respectively in liquid 0.2mL to be measured and the reaction vessel, and add 500 mg L
-1MDA solution 0.02mL at room temperature reacts 10-15 min, adds chromogenic reagent again, measures the absorbance of product at 630 nm places.But the shortcoming of this method is: 1) sample still need carry out the pre-treatment of cation exchange Solid-Phase Extraction, and is manual operations, and process is loaded down with trivial details and error is big; 2) a pre-treatment time is 40 min, and the enzymic catalytic reaction time is 10-15 min, and the chromogenic reaction time is 30 min, therefore analyzes oversize (80 min/ sample) consuming time, can't realize the quick mensuration of sample in batches; 3) contain acetic acid in the post cleaning fluid, can in cleaning fluid, part melamine wash-out in the extraction column be lost; In addition, Na
+Ion-exchange capacity less than-NH
3 +So the melamine amount of Na-MOPS eluent wash-out is less, these all can reduce mensuration sensitivity; 4) used enzyme reagent is expensive, and analysis cost increases, and is unfavorable for applying of method.
At present, the patent of the domestic preprocessing process of measuring at melamine in the dairy products has two (CN 201331461; CN 101776664).Both core technologies all are membrane extractions; One has been adopted the semi-permeable diaphragm extraction, and another is hollow fiber membrane extraction, and the design of two covering devices is basic identical; The former liquid to be measured is in the spe membrane pipe, is suspended in the middle of the sample bottle, and for former state to be extracted, the melamine molecule amount is less in the bottle, can enter in the liquid to be measured in the film by semi-permeable diaphragm; The latter's melamine enters film opposite side water by the organic phase in the hollow fiber fenestra, realizes the extraction to melamine in the sample; The extraction back is extracted the interior liquid to be measured of film and is carried out next step mensuration.But the weak point of these two kinds of methods is: 1) preprocessing process still is manual operations; 2) except melamine, still have some organic impurities to enter in the liquid to be measured by spe membrane in the sample, can't reach the purpose to the extraction of melamine high selectivity; 3) amount of samples is big; 4) the membrane extraction time long (140 min/ sample), analysis speed is slow; 5) n-octyl alcohol that uses in the extraction process, toluene equal solvent toxicity are big, health risk and environment.
In addition, the automatic on-line post micro-extraction system (Food Anal. Methods, 2010) that also has content of melamine in a kind of and the HPLC coupling mensuration dairy products.This pretreatment system is made up of two six-way valves, two pumps, kapillary polyalcohol integral pole and chromatographic resolution detection system.Polyalcohol integral pole is connected on the sampling ring of valve B, and sample injects sampling ring by syringe, simultaneously current-carrying (0.1% glacial acetic acid, v/v) flow through under the effect of the pump A sampling ring of valve A and valve B; Mobile flow through under the effect of pump B valve B, chromatographic column, detecting device provide background signal; Inject the position when the sampling ring of valve A is full of sample and switches to, sample is promoted the sampling ring that enters valve B by current-carrying; Melamine is adsorbed on the integral post by ion-exchange in this process; Valve B switches to and injects the position, flows and flows through extraction column, wherein NH mutually
4 +Melamine in the post is exchanged, and flowed and bring chromatographic column mutually into and separate, detect.The method shortcoming is: 1) analysis speed is slow, only is 2 sample h
-12) too little (the 0.1 mL min of extraction process flow
-1), a large amount of organic impurities also are adsorbed in the extraction column when making the melamine extraction, can not reach the purpose that high selectivity extracts melamine; 3) wash-out flow low (0.1 mL min too
-1), cause the interior a large amount of organic impurities of extraction column to be entered chromatographic column by wash-out, this not only influences measurement result, also influences the serviceable life of chromatographic column; The mobile phase flow rate instantaneous variation was big when 4) valve B sampled, and can cause to measure system stability variation, chromatographic system pressure surge, influenced the life-span of instrument and chromatographic column; 5) eluent is sour environment (phase pH 2.5 flows), and the wash-out flow only is 0.1 mL min
-1, therefore, the melamine kation that is exchanged in the elution process also can exchange on extraction column again, causes the elute effect variation; 6) can't realize multicolumn use in parallel, realize accelerating analysis speed; 7) rate of extraction is slow, and impurity is more in the eluent, therefore is difficult to the mensuration system coupling beyond the chromatogram, and range of application is narrow.
Summary of the invention
The objective of the invention is to develop content of melamine quick automatic determining method in a kind of dairy products and and the device of this method of realization; solve the problem of present stage technology existence; realize the robotization of pre-treatment operation and the process of mensuration; simplify the operation; reduce reagent dosage; be beneficial to environmental protection, improve analysis speed, precision and accuracy.
Technical scheme of the present invention is made up of determinator and assay method.
Measuring principle of the present invention: melamine (C
3N
3-(NH
2)
3) be alkaline compound, three-NH under sour environment (pH＜7.0) in the melamine molecule
2Be converted into-NH+ 3, namely melamine is to have (C with cationic form
3N
3-(NH+ 3)
3), so can realize the enrichment of melamine in the sample effectively by ion-exchange reactions; Therefore, the present invention has selected to have the sulfonic acid group (R-SO of ion exchanging function
3-H) mixed type cation exchange solid extracting agent is as the filler of extraction column.During mensuration, use ammonification methanol solution (NH+ 4) with the R-SO on the filler in the extraction column earlier
3-H becomes R-SO
3-NH
4, when samples of latex flows through extraction column, (NH+ 3) in the sample
3-C
3N
3With the R-SO on the filler in the extraction column
3-NH
4Exchange, form R-SO
3-(NH+ 3)
3-C
3N
3, and be adsorbed on the extraction column; Simultaneously, because samples of latex also contains some organic principles, in the example enrichment process, also can be adsorbed on the matrix of extraction column by Van der Waals force and stay in the post, the material that other does not exchange in the samples of latex then directly flows out extraction column; When cleaning fluid flow through extraction column, a part of organic impurities that adsorbs by Van der Waals force was dissolved, discharges outside the extraction column by methyl alcohol, and the melamine of ion-exchange is still stayed in the extraction column; When eluent flows through extraction column, NH+ 4 wherein and the R-SO in the post
3-(NH+ 3)
3-C
3N
3Carry out ion-exchange again, with (NH+ 3)
3-C
3N
3Exchange is got off; (NH+ 3)
3-C
3N
3Under the alkaline eluant environment, be converted into neutral C
3N
3-(NH
2)
3, and be dissolved in the methyl alcohol, and the melamine molecule of this moment can't exchange on extraction column again, guaranteed the completeness of ion-exchange.The melamine that exchanges together flows out extraction column with the form of " concentrating sample plug " with eluent, directly enters the sampling ring in second device unit (B), carries out quantitatively, separates, detects.The acidity condition of liquid chromatogram measuring is pH 3.0 in second device unit (B), and melamine becomes (NH+ 3) again
3-C
3N
3, and in flowing mutually sodium heptanesulfonate by static be combined (NH+ 3 and-SO-3) form nonpolar ionic compound, in reverse-phase chromatographic column, well kept and separated; The response signal of liquid chromatography is relevant with the concentration of melamine in the concentrating sample plug, therefore, under certain pre-service and condition determination, melamine concentration is linear in the response signal of liquid chromatography and the samples of latex, according to this response signal, can obtain the concentration of melamine in the samples of latex; Repeat said procedure, can carry out next The pretreatment.
Determinator of the present invention: it is made up of first device unit (A) and second device unit (B).First device unit (A) is by pump A, pump B, eluent, samples of latex, the post cleaning fluid, the eluent inlet tube, the eluent pump line, the eluent outlet, the sample inlet pipe, the sample pump line, the sample export pipe, the filter washing water inlet pipe, the cleaning fluid pump line, the rinse liquid outlet pipe, three-way connector, the threeway outlet, multifunction valve, first connecting pipe, second connecting pipe, filtrator, the first waste discharge mouth, the second waste discharge mouth, the 3rd connecting pipe, the 4th connecting pipe, extraction column 1, extraction column 2, the 5th connecting pipe, the 6th connecting pipe, the 7th connecting pipe constitutes.Second device unit (B) by mobile phase, flow go into mutually that valve pipe, pump C, sampling valve, sampling quantitatively encircle, the 3rd waste discharge mouth, chromatographic column entrance connecting pipe, chromatographic column, chromatographic column outlet connecting pipe, flow type fluorescence detector, computing machine, the 4th waste pipe form (as Fig. 1).
Among the present invention, quantitatively ring, the 3rd waste discharge mouth are connected the eluent inlet tube successively with eluent pump line, eluent outlet, the 6th connecting pipe, extraction column 1, the 3rd connecting pipe, second connecting pipe, first connecting pipe, filtrator, the 7th connecting pipe, sampling; The sample inlet pipe is connected successively with sample pump line, sample export pipe; The filter washing water inlet pipe is connected successively with cleaning fluid pump line, rinse liquid outlet pipe; Samples of latex and post cleaning fluid converge at the threeway outlet of three-way connector, and discharge afterwards by the 4th connecting pipe, extraction column 2, the 5th connecting pipe, the second waste discharge mouth of multifunction valve; Flow and to go into the valve pipe mutually and be connected (as Fig. 1) successively with pump C, sampling valve, chromatographic column entrance connecting pipe, chromatographic column, chromatographic column outlet connecting pipe, flow type fluorescence detector, the 4th waste pipe.
In the present invention, the example enrichment stream of extraction column 1 is formed by connecting by sample inlet pipe, sample pump line, sample export pipe, three-way connector, threeway outlet, multifunction valve, the 3rd connecting pipe, extraction column 1, the 6th connecting pipe, the first waste discharge mouth.Extraction column 1 cleans stream, is formed by connecting by filter washing water inlet pipe, cleaning fluid pump line, rinse liquid outlet pipe, three-way connector threeway outlet connecting pipe, multifunction valve, the 3rd connecting pipe, extraction column 1, the 6th connecting pipe, multifunction valve, the first waste discharge mouth; The wash-out stream of extraction column 1 is formed by connecting by eluent inlet tube, eluent pump line, eluent outlet, multifunction valve, the 6th connecting pipe, extraction column 1, the 3rd connecting pipe, and the sampling of second connecting pipe of its outlet by multifunction valve, first connecting pipe, filtrator, the 7th connecting pipe, sampling valve quantitatively encircles connection; The example enrichment stream of extraction column 2 is formed by connecting by the second waste discharge mouth of sample inlet pipe, sample pump line, sample export pipe, three-way connector, threeway outlet, multifunction valve, the 4th connecting pipe, extraction column 2, the 5th connecting pipe, multifunction valve; The second waste discharge mouth of the purge flow route filter washing water inlet pipe of extraction column 2, cleaning fluid pump line, rinse liquid outlet pipe, three-way connector threeway outlet connecting pipe, multifunction valve, the 4th connecting pipe, extraction column 2, the 5th connecting pipe, multifunction valve is formed by connecting; The wash-out stream of extraction column 2 is formed by connecting by eluent inlet tube, eluent pump line, eluent outlet, multifunction valve, the 5th connecting pipe, extraction column 2, the 4th connecting pipe, first connecting pipe of its outlet by multifunction valve, filtrator, the 7th connecting pipe, quantitatively encircles with the sampling of sampling valve and to be connected; The phase stream that flows is gone into valve pipe, sampling valve, chromatographic column entrance connecting pipe, chromatographic column, chromatographic column outlet connecting pipe, flow type fluorescence detector, the connection of the 4th waste discharge mouth mutually by flowing; Measured result is by Computer Processing.The rotation of multifunction valve among the present invention, sampling valve, pump A, pump B, pump C or stop to be computerizedd control.
Assay method of the present invention: when first device unit (A) when coming into operation, the first step, pump A rotates, pump B stops, multifunction valve is in position I, first samples of latex is under the dynamic action of pump A, by the sample inlet pipe, the sample pump line, the sample export pipe, enter three-way connector, again through the threeway outlet, the 4th connecting pipe of multifunction valve, enter extraction column 2, cation exchange group generation ion-exchange in melamine in the sample and the extraction column 2 on the filler, Jiao Huan material is not through the 5th connecting pipe, second waste pipe of multifunction valve is discharged, extraction column 2 this state through certain hour to samples of latex in melamine carry out enrichment; Meanwhile, eluent is under the dynamic action of pump A, the 6th connecting pipe by eluent inlet tube, eluent pump line, eluent outlet, multifunction valve, enter extraction column 1, extraction column 1 is regenerated, and then through the 3rd connecting pipe, second connecting pipe, first connecting pipe, filtrator, the 7th connecting pipe of multifunction valve, the sampling that flows into sampling valve in second device unit (B) quantitatively encircles, discharge from the 3rd waste discharge mouth at last, extraction column 1 is in the reproduced state of filler; Second step, pump A stops, pump B rotates, multifunction valve still is in position I, the post cleaning fluid is under the dynamic action of pump B, by filter washing water inlet pipe, cleaning fluid pump line, rinse liquid outlet pipe, enter three-way connector, again through the 4th connecting pipe of threeway outlet, multifunction valve, enter extraction column 2, to remain in the extraction column, not permutable other water-soluble or oil-soluble impuritieses wash out, discharge through the second waste discharge mouth of the 5th connecting pipe, multifunction valve then, extraction column 2 is in the cleaning state of filler; Extraction column 1 still is in reproduced state; The 3rd step, pump A rotates, pump B stops, multifunction valve switches to position II, eluent passes through the eluent inlet tube under the dynamic action of pump A, the eluent pump line, the eluent outlet, the 5th connecting pipe of multifunction valve, enter extraction column 2, the melamine generation ion-exchange of adsorbing on the filler in the kation in the eluent and the extraction column 2, in filler regeneration, melamine is eluted, and flow out from the 4th connecting pipe with eluent with the form of concentrating sample plug, then, first connecting pipe through multifunction valve, filtrator, the 7th connecting pipe, the sampling that flows into sampling valve quantitatively encircles, and carries out the quantitative of sample volume, discharge from the 3rd waste discharge mouth at last, extraction column 2 is in the melamine wash-out, the state of filler regeneration; Meanwhile, second samples of latex is under the dynamic action of pump A, by sample inlet pipe, sample flow pump line, sample export pipe, enter three-way connector, again through the 3rd connecting pipe of threeway outlet, multifunction valve, enter extraction column 1, ion-exchange takes place in the melamine in the sample in extraction column 1, Jiao Huan material is discharged through first waste pipe of the 6th connecting pipe, multifunction valve, extraction column 1 this state through certain hour to second emulsion in melamine carry out enrichment; In this process, pump C rotates continuously, sampling valve is in the sampling location, flow under the effect of pump C through mobilely going into valve pipe, sampling valve, chromatographic column entrance connecting pipe mutually, entering chromatographic column, flow through the flow type fluorescence detector through the chromatographic column outlet connecting pipe again, flowed out by the 4th waste discharge mouth at last, response signal provides a stable baseline; When the melamine " concentrating sample plug " from the eluent that two extraction columns flow out just in time is in the sampling ring of second device unit (B) respectively, sampling valve switches to the injection phase, " sample plug " that to inject mutually that flow advances chromatographic column, further separate, the formula that circulates then fluorescence detector detects absorbance, flows out from the 4th waste pipe at last; Measurement result is handled and exported to measured curve by computing machine according to the linear equation that stores; The computing machine while is according to the rotation of procedure auto-control valve and pump.
Each ingredient architectural feature of the present invention is as follows:
Among the present invention the enrichment of two extraction columns, cleaning, elution process all under the control of computing machine continuously, automatically, hocket.The length of extraction column is that 30 ~ 100 mm, internal diameter are 2 ~ 5 mm, and packing material size is 20 ~ 60 μ m, and quality is 30 ~ 100 mg.The example enrichment of two extraction columns is opposite with the flow direction of sample wash-out, can strengthen the exchange capacity of melamine on the interior filler of eluent and extraction column, improves the sensitivity of measuring; Filler in the extraction column is various solid phase mixing type cation exchange extractants that have the cation exchange effect etc.
Post cleaning fluid of the present invention be used for to clean samples of latex other water-soluble and liposoluble substances except melamine, is made of the mixed liquor of methyl alcohol and ultrapure water; Its flow is 0.5 ~ 2.5 mL min
-1
Eluent of the present invention is used for wash-out and is adsorbed on the melamine on the filler in the extraction column, and by the ammonification methyl alcohol formation of 1 ~ 10% (v/v), its flow is 0.5 ~ 5 mL min
-1Eluent flows into multifunction valve through eluent inlet tube, eluent pump line, eluent outlet, enter extraction column 1 and extraction column 2 by the 6th connecting pipe and the 5th connecting pipe respectively then, the melamine generation ion-exchange of adsorbing in kation wherein and the extraction column, the melamine that exchanges flows out with eluent with " concentrating sample plug " form, directly enter in the quantitative ring of sampling of sampling valve, carry out quantitatively, inject, separate and detection; This " concentrating sample plug " can directly enter in the quantitative ring of sampling of chromatographic system, Flow Injection Analysis system; The eluent that flows out extraction column need not to dry again, step such as dissolving again.
Second connecting pipe of the present invention is removed, on the two ends of the multifunction valve that will dock with second connecting pipe are stifled with solid connecting screw, the 3rd connecting pipe and extraction column 1 are removed, one end of the 6th connecting pipe butt joint extraction column 1 is inserted eluent, can form the continuously automatic preprocessing system that a kind of list props up extraction column; In like manner, will remove corresponding to the relevant stream of extraction column 2, also can form the continuously automatic preprocessing system of another kind of single extraction column.
First device unit of the present invention (A) can with various liquid phases or the direct coupling of gas chromatograph; Also available reaction coil pipe substitutes chromatographic column, and current-carrying instead of flow phase is added suitable reagent stream, and second device unit (B) is become coupling again after flow injection spectrophotometric system or the flow injection fluorophotometric system.
The pipeline material of connected system of the present invention is plastic straws such as tygon, teflon, and the internal diameter of various connecting pipes is in 0.5 ~ 1.5 mm scope; The sampling quantitatively volume of ring is 20 ~ 200 μ L, and the flow of samples of latex is 0.5 ~ 2.0 mL min
-1The pump that uses is a plurality of hyperchannels or a plurality of single channel peristaltic pump, a plurality of ram pump or other fluid power plants.
Melamine measurement range of the present invention is 0.5～50 mg L
-1, linearly dependent coefficient (r)〉and 0.9990; Relative standard deviation (RSD) is less than 3.88%(n=11); Analysis speed 30 sample h
-1About.
Advantage of the present invention and good effect are: example enrichment, extraction column clean, the mensuration of sample wash-out and melamine " concentrating sample plug " can both be continuously, automatically, hocket, install easy and simple to handle, finding speed soon, favorable reproducibility, highly sensitive.Characteristics of the present invention are:
A) hocket automatically continuously at the following pair extraction column of computer control that example enrichment, post clean, the process of sample wash-out.To sample pre-treatments, consequently little, the RSD (＜3.88%) of error is better than National Standard Method set-point (＜10%) with the present invention.
B) consumption of cleaning fluid and eluent is few.The cleaning fluid consumption is from 6 mL time of National Standard Method
-1Be reduced to 0.5 mL time
-1; The eluent consumption is from 6 mL time of National Standard Method
-1Be reduced to 0.75 mL time
-1This has not only reduced the harm of analyst's health, has also reduced the pollution to environment simultaneously.
C) analysis speed of the present invention is fast.Sample preparation and finding speed are from 2 ~ 3 sample h of National Standard Method
-1Be increased to 30 sample h
-1About.Can be applicable to rapid screening and the analysis of dairy products sample in enormous quantities.
D) the eluent consumption only is 0.75 mL time among the present invention
-1, methanol usage only is 0.7 mL time
-1, the impurity in the eluent is minimum, when using liquid chromatogram measuring, can not influence measurement result.
E) eluent that flows out from extraction column carries sampling that melamine " concentrating sample plug " can directly enter detection system quantitatively in the ring, carries out quantitatively, injects, separates and detects, and need not oven dry and dissolving step again.This has not only been avoided organic solvent volatilization problem of environment pollution caused, has also shortened the pre-treatment time of sample simultaneously, has improved whole analysis speed.
F) realized the repeated use of extraction column at flow path system.This has not only reduced cost of determination, waste disposal cost, the wasting of resources significantly, and has reduced the source of error of pre-treatment, has improved the reappearance of method and the accuracy of net result.
G) example enrichment is opposite at extraction column with the flow direction of sample wash-out, and the melamine eluting rate is improved.When eluent flowed into extraction column with the reverse direction of example enrichment, near the quick wash-out of high concentration melamine that is easy to be enriched in the extraction column entrance came out; The shortening of elution time can reduce the degree that melamine is diluted again in " concentrating the sample plug ", finally causes the raising of ion-exchanging efficiency and mensuration sensitivity.
H) simple, the easy operating of flow path system of the present invention, be easy to assembling, reliability height, extraction column long service life.
I) eluent that flows out extraction column is directly measured, dissolving again after needing to handle through oven dry earlier, and this not only causes organic solvent volatilization contaminated environment, has also increased the pre-treatment time of sample simultaneously, has influenced whole analysis speed.
J) the automatic pretreating device can be separately measured as melamine in a kind of emulsion of first device unit of the present invention (A) uses, also can be directly and liquid chromatograph, gas chromatograph, flow injection spectrophotometer, the coupling of flow injection fluorophotometer.
The present invention is applicable to the quick automatic determining of content of melamine in the dairy products; Related scientific domain has multiple subjects such as chemical instruments, analytical chemistry, is the synthetic study achievement of cross discipline, has very important use meaning and social value.
Description of drawings
Fig. 1. content of melamine quick automatic determining device synoptic diagram in the dairy products
1 pump A among the figure, 2 pump B, 3 eluents, 4 samples of latex, 5 post cleaning fluids, 6a eluent inlet tube, 6 eluent pump lines, 6b eluent outlet, 7a sample inlet pipe, 7 sample pump lines, 7b sample export pipe, 8a filter washing water inlet pipe, 8 cleaning fluid pump lines, 8b rinse liquid outlet pipe, 9 three-way connectors, 10 threeway outlets, 11 multifunction valves, 12 first connecting pipes, 13 second connecting pipes, 14 filtrators, 15 first waste discharge mouths, 16 second waste discharge mouths, 17 the 3rd connecting pipes, 18 the 4th connecting pipes, 19 extraction columns 1,20 extraction columns 2,21 the 5th connecting pipes, 22 the 6th connecting pipes, 23 the 7th connecting pipes constitute; Device unit (B) is flowed by 24 mobile phases, 25 and goes into valve pipe, 26 pump C, 27 sampling valves, 28 samplings quantitatively ring, 29 the 3rd waste discharge mouths, 30 chromatographic column entrance connecting pipes, 31 chromatographic columns, 32 chromatographic column outlet connecting pipes, 33 flow type fluorescence detectors, 34 computing machines, 35 the 4th waste discharge mouths mutually.
The canonical plotting of Fig. 2 embodiment 1 melamine
Fig. 3 embodiment 2 sample flows are to the curve map of sensitivity influence
Fig. 4 embodiment 3 sample volumes are to the curve map of sensitivity influence
Fig. 5 embodiment 4 cleaning fluid consumptions are to the curve map of sensitivity influence
Fig. 6 embodiment 5 cleaning fluid flows are to the curve map of sensitivity influence
Fig. 7 embodiment 6 eluent flows are to the curve map of sensitivity influence
The concentration of ammoniacal liquor is to the curve map of sensitivity influence in Fig. 8 embodiment 7 eluents
Embodiment
By reference to the accompanying drawings embodiments of the present invention are further described:
Present embodiment is to investigate concentrated effect of the present invention with the melamine standard solution of variable concentrations respectively.The experiment condition of automatic preprocessing system: post cleaning fluid (5) is the mixed liquor of ultrapure water and methyl alcohol (1+1), and its flow is 1.05 mL min
-1, consumption is 2.5 mL; Samples of latex (4) volume is 6 mL, and its flow is 1.2 mL min
-1Eluent (3) is 7.0% (v/v) ammonification methanol solution, and its flow is 1.48 mL min
-1, elution time is 30s; Extraction column 2(20) length is that 40 mm, internal diameter are 3 mm, and packing material size is 45 μ m, and quality is 60 mg; First connecting pipe (12) has used long 25 cm, the polyfluortetraethylene pipe of internal diameter 0.8 mm; The length of threeway outlet (10), first connecting pipe (12), the 4th connecting pipe (18), the 5th connecting pipe (21) and the 7th connecting pipe (23) is respectively 25,25,20,13 and 25 cm, and internal diameter is 0.8 mm; The experiment condition of liquid chromatographic system: the phase (24) that flows is acetonitrile-sodium heptanesulfonate/citrate buffer solution (volume ratio 15+85), and its flow is 0.8 mL min
-1The sampling quantitatively volume of ring (28) is 60 μ L; The detection wavelength of flow type fluorescence detector (30) is 237 nm; Chromatographic column (31) is C
8(5 μ m, 4.6 * 150 mm).The device unit (A) of (see figure 1) of the present invention is connected into the continuously automatic preprocessing system of single extraction column, mark liquid as specimen (concentration range: 0.5～50 mg L with identical melamine
-1).At first, directly melamine is marked liquid by hand and injected liquid chromatographic system, obtain a series of absorbances; Then, by device unit (A) melamine is marked again and injected liquid chromatographic system after the liquid enrichment pre-service automatically, obtain another serial absorbance; The results are shown in Figure 2.As can be seen, measure the melamine slope of standard curve that obtains with the present invention and will be higher than manual direct injection, of the present invention highly sensitive in manual method, i.e. the automatic pre-service that shows melamine mark liquid really of the present invention.
Present embodiment is measured reappearance of the present invention, four kinds of dairy products that contain melamine and recovery of standard addition.The measurement result of reappearance (n=11) sees Table 1, and recovery of standard addition the results are shown in Table 2.According to table 1 data as can be seen, the RSD of measurement result of the present invention＜3.88%, namely precision is far above the set-point (RSD＜10.0%) of GB.According to table 2 data as can be seen, recovery of standard addition of the present invention is between 95.4 ~ 108.1%, and the result is satisfactory.As seen the present invention can satisfy the pre-treatment that content of melamine is measured in the dairy products fully and measure requirement fast.
Present embodiment is respectively with 5 mg L with the present invention
-1, 20 mg L
-1The melamine titer has been investigated the effect of extraction column enrichment melamine under different sample flows as specimen (4).Experiment condition: the fixed sample volume is 8.0mL, and post cleaning fluid (5) is that (50/50, v/v), scavenging period is 200s for water and methyl alcohol mixed liquor; Cleaning flow is 0.9 mL min
-1, eluent (3) is the ammonification methyl alcohol of 5.0% (v/v), its flow is 1.17mL min
-1, elution time is 45s.Experimental result is seen Fig. 3.As can be seen, in the present invention, along with the increase of sample flow, absorbance reduces after increasing gradually earlier gradually; When sample flow is 1.2mL min
-1The time, the absorbance maximum.That is, this moment extraction column the melamine rich best results.
Embodiment 4
Present embodiment is with 20 mg L at device of the present invention
-1The melamine titer investigated different sample volumes to the influence of extraction column enrichment melamine as specimen.Experiment condition: sample flow is 1.2 mL min
-1, post cleaning fluid (5) is that (50/50, v/v), the post scavenging period is 200s, and cleaning flow is 0.9 mL min for water and methyl alcohol mixed liquor
-1Eluent (3) is the ammonification methyl alcohol of 5.0% (v/v), and its flow is 1.17 mL min
-1, elution time is 45s.Experimental result is seen Fig. 4.As can be seen, along with the increase of sample volume (4), absorbance increases gradually, when sample volume during greater than 12 mL, absorbance tends to be steady, namely, under the condition of selected extraction column volume, packing quality, this moment, extraction column reached capacity to the accumulation ability of melamine.
Present embodiment is to investigate post cleaning fluid (5) consumption to the influence of extraction column enrichment melamine at device of the present invention.Experiment condition: 5 mg L
-1With 20 mg L
-1Melamine mark liquid as specimen (4), its flow is 1.2 mL min
-1, volume is 6 mL; The concentration of ammoniacal liquor is 5.0% (v/v) in the eluent (3), and its flow is 1.17 mL min
-1, elution time is 45s; Post cleaning fluid (5) is that (1+1, v/v), its flow is 0.9 mL min for water and methyl alcohol mixed liquor
-1Experimental result is seen Fig. 5.As can be seen, when the cleaning fluid flow was certain, along with the increase of cleaning fluid consumption, absorbance reduced gradually, and when cleaning fluid consumption during greater than 2.25 mL, it is constant that absorbance is tending towards.That is, under selected flow, the cleaning fluid of 2.25 mL can thoroughly clean other residuals in the extraction column.
Present embodiment is to investigate the cleaning fluid flow to the influence of extraction column enrichment melamine at device of the present invention.Experiment condition: 5mg L
-1With 20mg L
-1Melamine mark liquid as specimen (4), its flow is 1.2 mL min
-1, volume is 6 mL; Post cleaning fluid (5) is that (1+1, v/v), its flow is 0.9 mL min for water and methyl alcohol mixed liquor
-1, consumption is 2.5 mL; The concentration of ammoniacal liquor is 5.0% (v/v) in the eluent (3), and its flow is 1.17 mL min
-1, elution time is 45s.Experimental result is seen Fig. 6.As can be seen, clean flow at 0.54 ~ 1.05 mL min
-1When changing in the scope, absorbance is almost constant; This shows, when cleaning flow less than 1.05 mL min
-1The time, the stability that is adsorbed on the melamine on the filling surface is not exerted an influence; When this flow greater than 1.05 mL min
-1The time, along with the increase of flow, absorbance begins to reduce gradually; This shows that under selected consumption, high flow capacity is enough to make the melamine that adsorbs in the extraction column to be cleaned, and has influenced the concentration effect of melamine, has caused absorbance decline.
Embodiment 7
Present embodiment is to investigate eluent (3) flow to the influence of extraction column enrichment melamine at device of the present invention.Experiment condition: 5 mg L
-1With 20 mg L
-1Melamine mark liquid as specimen (4), its flow is 1.2 mL min
-1, volume is 6 mL; Post cleaning fluid (5) is that (1+1, v/v), its flow is 0.9 mL min for water and methyl alcohol mixed liquor
-1, consumption is 2.5 mL; The concentration of ammoniacal liquor is 5.0% (v/v) in the eluent (3), and elution time is 45s.Experimental result is seen Fig. 7.As can be seen, along with the increase of eluent flow, the absorbance of melamine increases afterwards earlier and reduces, when flow is 1.48 mL min
-1The time, absorbance has maximal value.This shows, under the consumption of setting, and 1.48 mL min
-1The eluent flow melamine of enrichment in the extraction column all can be eluted, send into detecting device.
Present embodiment is to investigate in the eluent ammonia concn to the influence of extraction column enrichment melamine at device of the present invention.Experiment condition: 5mg L
-1With 20 mg L
-1Melamine mark liquid as specimen (4), its flow is 1.2 mL min
-1, volume is 6 mL; Post cleaning fluid (5) is that (1+1, v/v), its flow is 0.9 mL min for water and methyl alcohol mixed liquor
-1, consumption is 2.5 mL; Eluent (3) flow is 1.48 mL min
-1, elution time is 45s.Experimental result is seen Fig. 8.As can be seen, along with the increase of ammonia concn in the eluent, absorbance increases gradually, when ammonia concn greater than 7.0% the time, continue to increase ammonia concn, the absorbance increase slows down.This phenomenon shows that under selected condition, ammonia concn directly influences the elution amount of melamine on the extraction column.
Present embodiment is to have investigated two extraction columns (19,20) to the reappearance of extraction column enrichment melamine at device of the present invention.Experiment condition: 5 mg L
-1With 15 mg L
-1Melamine mark liquid as specimen (4), its flow is 1.2 mL min
-1, enrichment time 60s; Post cleaning fluid (5) is that (1+1, v/v), its flow is 1.05 mL min for water and methyl alcohol mixed liquor
-1, scavenging period is 30s; Eluent (3) flow is 1.48 mL min
-1, elution time 30s.The condition of flow injection ultraviolet detection system: current-carrying is that (7.0%, v/v), its flow is 3.0 mL min to ammonification methyl alcohol
-1, sampling volume is 60 uL, and wavelength is 237 nm, and mixing coil pipe is 200 cm (internal diameter 0.5 mm), and pre-treating speed is 40 sample h
-1Experimental result sees Table 3.As can be seen, mark liquid as specimen (4) with the melamine of two kinds of variable concentrations, replication is 11 times respectively, and the RSD value that obtains shows that less than 3.08% the reappearance of the two automatic pre-service melamine of extraction column samples is fine.
Claims (9)
1. content of melamine quick automatic determining device in the dairy products is characterized in that: be made up of first device unit and second device unit; First device unit is by pump A(1), pump B(2), eluent (3), samples of latex (4), post cleaning fluid (5), eluent inlet tube (6a), eluent pump line (6), eluent outlet (6b), sample inlet pipe (7a), sample pump line (7), sample export pipe (7b), filter washing water inlet pipe (8a), cleaning fluid pump line (8), rinse liquid outlet pipe (8b), three-way connector (9), threeway outlet (10), multifunction valve (11), first connecting pipe (12), second connecting pipe (13), filtrator (14), the first waste discharge mouth (15), the second waste discharge mouth (16), the 3rd connecting pipe (17), the 4th connecting pipe (18), extraction column 1(19), extraction column 2(20), the 5th connecting pipe (21), the 6th connecting pipe (22), the 7th connecting pipe (23) constitutes; Second device unit by mobile phase (24), flow and to go into valve pipe (25), pump C(26 mutually), sampling valve (27), quantitatively ring (28), the 3rd waste discharge mouth (29), chromatographic column entrance connecting pipe (30), chromatographic column (31), chromatographic column outlet connecting pipe (32), flow type fluorescence detector (33), computing machine (34), the 4th waste pipe (35) are formed in sampling; Extraction column 1(19) example enrichment stream is by sample inlet pipe (7a), sample pump line (7), sample export pipe (7b), three-way connector (9), threeway outlet (10), multifunction valve (11), the 3rd connecting pipe (17), extraction column 1(19), the 6th connecting pipe (22), the first waste discharge mouth (15) be formed by connecting; Extraction column 1(19) purge flow route filter washing water inlet pipe (8a), cleaning fluid pump line (8), rinse liquid outlet pipe (8b), three-way connector (9) threeway outlet connecting pipe (10), multifunction valve (11), the 3rd connecting pipe (17), extraction column 1(19), the 6th connecting pipe (22), multifunction valve (11), the first waste discharge mouth (15) be formed by connecting; Extraction column 1(19) the wash-out stream is by eluent inlet tube (6a), eluent pump line (6), eluent outlet (6b), multifunction valve (11), the 6th connecting pipe (22), extraction column 1(19), the 3rd connecting pipe (17) is formed by connecting, the sampling of second connecting pipe (13) of its outlet by multifunction valve (11), first connecting pipe (12), filtrator (14), the 7th connecting pipe (23), sampling valve (27) quantitatively encircles (28) connection; Extraction column 2(20) example enrichment stream is by sample inlet pipe (7a), sample pump line (7), sample export pipe (7b), three-way connector (9), threeway outlet (10), multifunction valve (11), the 4th connecting pipe (18), extraction column 2(20), the second waste discharge mouth (16) of the 5th connecting pipe (21), multifunction valve (11) is formed by connecting; Extraction column 2(20) purge flow route filter washing water inlet pipe (8a), cleaning fluid pump line (8), rinse liquid outlet pipe (8b), three-way connector (9) threeway outlet connecting pipe (10), multifunction valve (11), the 4th connecting pipe (18), extraction column 2(20), the second waste discharge mouth (16) of the 5th connecting pipe (21), multifunction valve (11) is formed by connecting; Extraction column 2(20) wash-out stream is by eluent inlet tube (6a), eluent pump line (6), eluent outlet (6b), multifunction valve (11), the 5th connecting pipe (21), extraction column 2(20), the 4th connecting pipe (18) is formed by connecting, first connecting pipe (12), filtrator (14), seven connecting pipe (23) of its outlet by multifunction valve (11), quantitatively encircle (28) with the sampling of sampling valve (27) and be connected; The phase stream that flows is gone into valve pipe (25), sampling valve (27), chromatographic column entrance connecting pipe (30), chromatographic column (31), chromatographic column outlet connecting pipe (32), flow type fluorescence detector (33), the 4th waste discharge mouth (35) mutually and is connected and composed by flowing; Measured result is handled by computing machine (34); Multifunction valve among the present invention (11), sampling valve (27), pump A(1), pump B(2), pump C(26) rotation or stop, with computing machine (34) control.
2. a right to use requires content of melamine quick automatic determining method in the dairy products of 1 described apparatus for automatically measuring, it is characterized in that: when first device unit comes into operation, the first step, pump A(1) rotates, pump B(2) stops, multifunction valve (11) is in position I, first samples of latex (4) is at pump A(1) dynamic action under, by sample inlet pipe (7a), sample pump line (7), sample export pipe (7b), enter three-way connector (9), again through threeway outlet (10), the 4th connecting pipe (18) of multifunction valve (11), enter extraction column 2(20), the melamine of (4) and extraction column 2(20 in the sample) in cation exchange group generation ion-exchange on the filler, Jiao Huan material is not through the 5th connecting pipe (21), second waste pipe (16) of multifunction valve (11) is discharged, extraction column 2(20) this state through certain hour to samples of latex in melamine carry out enrichment; Meanwhile, eluent (3) is at pump A(1) dynamic action under, by eluent inlet tube (6a), eluent pump line (6), eluent outlet (6b), the 6th connecting pipe (22) of multifunction valve (11), enter extraction column 1(19), to extraction column 1(19) regenerate, then through the 3rd connecting pipe (17) of multifunction valve (11), second connecting pipe (13), first connecting pipe (12), filtrator (14), the 7th connecting pipe (23), the sampling of sampling valve (27) quantitatively encircles (28) in the inflow device unit (B), discharge extraction column 1(19 at last from the 3rd waste discharge mouth (29)) be in the reproduced state of filler; Second step, pump A(1) stops, pump B(2) rotates, multifunction valve (11) still is in position I, post cleaning fluid (5) is at pump B(2) dynamic action under, by filter washing water inlet pipe (8a), cleaning fluid pump line (8), rinse liquid outlet pipe (8b), enter three-way connector (9), again through threeway outlet (10), the 4th connecting pipe (18) of multifunction valve (11), enter extraction column 2(20), to remain in the extraction column, not permutable other water-soluble or oil-soluble impuritieses wash out, then through the 5th connecting pipe (21), the second waste discharge mouth (16) of multifunction valve (11) is discharged, extraction column 2(20) be in the cleaning state of filler; Extraction column 1(19) still is in reproduced state; The 3rd step, pump A(1) rotates, pump B(2) stops, multifunction valve (11) switches to position II, eluent (3) is at pump A(1) dynamic action under by eluent inlet tube (6a), eluent pump line (6), eluent outlet (6b), the 5th connecting pipe (21) of multifunction valve (11), enter extraction column 2(20), kation in the eluent (3) and extraction column 2(20) the melamine generation ion-exchange of adsorbing on the interior filler, in filler regeneration, melamine is eluted, and flow out from the 4th connecting pipe (18) with eluent (3) with the form of concentrating sample plug, then, first connecting pipe (12) through multifunction valve (11), filtrator (14), the 7th connecting pipe (23), the sampling that flows into sampling valve (27) quantitatively encircles (28), carry out the quantitative of sample volume, discharge extraction column 2(20 at last from the 3rd waste discharge mouth (29)) be in the melamine wash-out, the state of filler regeneration; Meanwhile, second samples of latex (4) is at pump A(1) dynamic action under, by sample inlet pipe (7a), sample flow pump line (7), sample export pipe (7b), enter three-way connector (9), again through threeway outlet (10), the 3rd connecting pipe (17) of multifunction valve (11), enter extraction column 1(19), melamine in the sample is at extraction column 1(19) in ion-exchange takes place, Jiao Huan material is not through the 6th connecting pipe (22), first waste pipe (15) of multifunction valve (11) is discharged, extraction column 1(19) this state through certain hour to second emulsion in melamine carry out enrichment; In this process, pump C(26) rotates continuously, sampling valve (27) is in the sampling location, flow phase (24) at pump C(26) effect under go into valve pipe (25), sampling valve (27), chromatographic column entrance connecting pipe (30) mutually through flowing, enter chromatographic column (31), flow through flow type fluorescence detector (33) through chromatographic column outlet connecting pipe (32) again, flowed out by the 4th waste discharge mouth (35) at last, response signal provides a stable baseline; When respectively from two extraction columns (19,20) the melamine concentrating sample plug in the eluent of Liu Chuing (3) just in time is in the sampling ring (28) of second device unit when interior, sampling valve (27) switches to the injection phase, the phase (24) that flows advances chromatographic column (31) with the concentrating sample plug that injects, further separate, the formula that circulates then fluorescence detector (33) detects absorbance, flows out from the 4th waste pipe (35) at last; Measurement result is handled and exported to measured curve by computing machine (34) according to the linear equation that stores; Computing machine (34) while is according to the rotation of procedure auto-control valve and pump; Eluent inlet tube (6a) and eluent pump line (6), eluent outlet (6b) the 6th connecting pipe (22), extraction column 1(19), the 3rd connecting pipe (17), second connecting pipe (13), first connecting pipe (12), filtrator (14), the 7th connecting pipe (23), quantitatively ring (28), the 3rd waste discharge mouth (29) are connected successively in sampling; Sample inlet pipe (7a) is connected successively with sample pump line (7), sample export pipe (7b); Filter washing water inlet pipe (8a) is connected successively with cleaning fluid pump line (8), rinse liquid outlet pipe (8b); Samples of latex (4) and post cleaning fluid (5) converge at the threeway outlet (10) of three-way connector (9), by the 4th connecting pipe (18), the extraction column 2(20 of multifunction valve (11)), the 5th connecting pipe (21), the second waste discharge mouth (16) discharge afterwards; Flow and to go into valve pipe (25) and pump C(26 mutually), sampling valve (27), chromatographic column entrance connecting pipe (30), chromatographic column (31), chromatographic column outlet connecting pipe (32), flow type fluorescence detector (33), the 4th waste pipe (35) be connected successively.
3. content of melamine quick automatic determining device in a kind of dairy products as claimed in claim 1, it is characterized in that: eluent (3) is through eluent inlet tube (6a), eluent pump line (6), eluent outlet (6b) flows into multifunction valve (11), enter extraction column 1 (19) and extraction column 2 (20) by the 6th connecting pipe (22) and the 5th connecting pipe (21) respectively then, the melamine generation ion-exchange of absorption in kation wherein and extraction column 1 (19) and the extraction column 2 (20), the melamine that exchanges flows out with eluent (3) with the concentrating sample plug form, the sampling that directly enters sampling valve (27) quantitatively encircles in (28), carries out quantitatively, inject, separate and detection; The sampling that this sample plug that concentrates can directly enter liquid chromatographic system or Flow Injection Analysis system quantitatively encircles in (28); The eluent (3) that flows out extraction column 1 (19) and extraction column 2 (20) need not to dry, dissolving step again, shortened minute, saved reagent dosage.
4. content of melamine quick automatic determining device in a kind of dairy products as claimed in claim 1, it is characterized in that: second connecting pipe (13) is removed, on the two ends of the multifunction valve that will dock with second connecting pipe (13) are stifled with solid connecting screw, the 3rd connecting pipe (17) and extraction column 1(19) remove, with the 6th connecting pipe (22) butt joint extraction column 1(19) an end insert eluent (3), forms a kind of based on extraction column 2(20) list prop up the continuously automatic preprocessing system of extraction column.
5. content of melamine quick automatic determining device in a kind of dairy products as claimed in claim 1, it is characterized in that: will be corresponding to extraction column 2(20) relevant stream remove, form another kind of based on extraction column 1(19) list prop up the preprocessing system automatically continuously of extraction column.
6. content of melamine quick automatic determining device in a kind of dairy products as claimed in claim 1 is characterized in that: with the direct coupling of liquid chromatograph; Substitute chromatographic column (31) with the reaction coil pipe, reagent current-carrying instead of flow phase becomes second device unit into coupling again after flow injection spectrophotometric system, the flow injection fluorophotometric system.
7. content of melamine quick automatic determining device in a kind of dairy products as claimed in claim 1, it is characterized in that: the pipeline material of connected system is tygon, polytetrafluoroethylplastic plastic tubule, the internal diameter of various connecting pipes is in 0.5 ~ 1.5 mm scope, and length is in 10 ~ 50 cm scopes; The sampling quantitatively volume of ring (28) is 20 ~ 200 μ L; The pump that uses is hyperchannel, single channel peristaltic pump, ram pump or other fluid power plants.
8. content of melamine quick automatic determining method in a kind of dairy products as claimed in claim 2 is characterized in that: the enrichment of extraction column 1 (19) and extraction column 2 (20), cleaning, elution process all under the control of computing machine (34) continuously, automatically, hocket; Extraction column 1 (19) and extraction column 2 (20) are mixed type cation exchange solid-phase extraction column, its length is that 30 ~ 100 mm, internal diameter are 2 ~ 5 mm, filler is polar polymer polystyrene/divinylbenzene matrix that bonding has sulfonic acid group, and its particle diameter is 20 ~ 60 μ m, and quality is 30 ~ 100 mg; The example enrichment of extraction column 1 (19) and extraction column 2 (20) is opposite with the flow direction of sample wash-out, has strengthened the exchange capacity that eluent (3) and extraction column 1 (19) and extraction column 2 (20) are gone up melamine, has increased the sensitivity of measuring; Filler in the extraction column has the cation exchange effect.
9. content of melamine quick automatic determining method in a kind of dairy products as claimed in claim 2, it is characterized in that: post cleaning fluid (5) be used for to clean samples of latex other water-soluble and liposoluble substances except melamine, is made of the mixed liquor of ultrapure water or methyl alcohol and ultrapure water; Its flow is 0.5 ~ 2.5 mL min
-1Eluent (3) is used for wash-out and is adsorbed on melamine on extraction column 1 (19) and extraction column 2 (20) the interior fillers, and by the formation of 1 ~ 10% (v/v) ammonification methyl alcohol, its flow is 0.5 ~ 5 mL min
-1The flow of samples of latex is 0.5 ~ 2.0 mL min
-1
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| CN102631797B (en) * | 2012-04-27 | 2015-02-18 | 四川大学 | Automatic regeneration device of suppression column used in low-pressure ion chromatography |
| CN103505907B (en) * | 2012-06-18 | 2015-12-02 | 宁波大学 | A kind of online solid phase micro-extraction method of flow injection and device thereof |
| CN106092927B (en) * | 2016-06-02 | 2018-10-26 | 四川大学 | A kind of melamine analysis method based on flow injection-optical detection |
| CN108535377A (en) * | 2018-04-11 | 2018-09-14 | 大连依利特分析仪器有限公司 | It is a kind of to automate quick detection device and rapid detection method |
| CN108548879B (en) * | 2018-04-11 | 2024-07-09 | 大连依利特分析仪器有限公司 | Automatic change rapid detection equipment |
| CN109541055B (en) * | 2018-11-15 | 2021-08-03 | 云南中烟工业有限责任公司 | On-line enrichment and analysis method for alkaloid compounds |
| CN109917035B (en) * | 2019-03-22 | 2022-02-18 | 肖传绪 | Elution device with pressure drop measurement function and application thereof |
| CN110201420B (en) * | 2019-06-27 | 2024-07-19 | 上海渔霁生物技术有限公司 | Chromatographic system and method for separating organic acid and organic acid ester |
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| CN101487797A (en) * | 2009-02-24 | 2009-07-22 | 中国检验检疫科学研究院 | Method for measuring melamine content in liquid example |
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| CN1776664A (en) * | 2003-08-13 | 2006-05-24 | 索尼株式会社 | System, method, equipment and program for distributing network communication data |
| CN101487797A (en) * | 2009-02-24 | 2009-07-22 | 中国检验检疫科学研究院 | Method for measuring melamine content in liquid example |
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