CN1322947A

CN1322947A - Mecury compound testing strip based on enzyme inhibiting reaction

Info

Publication number: CN1322947A
Application number: CN 01118580
Authority: CN
Inventors: 江桂斌; 时国庆
Original assignee: Research Center for Eco Environmental Sciences of CAS
Current assignee: Research Center for Eco Environmental Sciences of CAS
Priority date: 2001-06-05
Filing date: 2001-06-05
Publication date: 2001-11-21
Anticipated expiration: 2021-06-05
Also published as: CN1210556C

Abstract

The present invention belongs to the field of analysis and test and relates to one kind of developed mercury compound testing strip. The testing strip consists of two parts of polyester film carrier and reaction area and the reaction area includes one sheet of urease fixing acetyl cellulose film and urea and mycose adsorbing precise pH test paper. When used, the testing strip is soaked in solution to be tested and one blue ring will appear in the edge of the pH test paper and expand to the center with the time for the reaction area to become blue completely being positively correlated with the concentration of mercury compound in the solution. Being sensitive, specific, low in cost and convenient, the testing strip is suitable for use in trace test of inorganic mercury ion and organic mercury compound in water sample.

Description

Mercury compound detection strip based on enzyme inhibition reaction

The invention belongs to the technical field of analysis and test, and relates to development of a detection strip for quantitatively analyzing mercury compounds by using an enzyme inhibition color reaction. The test strip consists of two parts, namely a polyester film carrier and a reaction area, wherein the reaction area comprises a cellulose acetate film fixed with urease and a piece of precision pH test paper adsorbing urea and trehalose. When the test strip is used, the test strip is directly inserted into a sample solution to be tested, so that the solution is submerged in a reaction area, a blue ring can be seen at the edge of a pH test paper after two minutes, the blue ring gradually expands towards the center along with the reaction, and the time for the reaction area to completely turn blue is in positive correlation with the concentration of mercury ions in the sample solution. The detection strip has the characteristics of sensitivity, high specificity, low cost and convenient use. The detection strip is suitable for trace detection of mercury ions in an environmental water sample.

The background and current state of the art is generally as follows: at present, the detection of mercury ions in an environmental water sample is mainly realized by methods such as atomic absorption spectroscopy, atomic emission spectroscopy and the like. Although these methods have high sensitivity and accuracy, they require expensive large-scale instruments, complicated sample pretreatment processes, and high requirements on operators, which make them difficult to be used for field detection of environmental samples. To address this problem, simple and sensitive enzyme inhibition assays are used for the detection of mercury. Commonly used enzymes are urease, peroxidase, glucose oxidase, etc., wherein urease is the most studied one, and the measurement of mercury in a sample is mainly realized through the change of color, fluorescence and electrochemical properties caused by enzymatic reaction. Generally speaking, these methods have high sensitivity and selectivity, and are simple to operate. However, most of these methods cannot be used for direct detection of environmental samples due to interference of the matrix in the environmental samples, and still require appropriate pretreatment of the samples. The invention does not need to carry out complex pretreatment on the sample, does not need precise instruments and equipment, and does not need to master special professional skills by a user. References to this can be found in:

(1)W.L.Clevenger,B.W.Smith,and J.D.Winefordner,

Crit.Rev.Anal.Chem.,1997,27(1),1-26

(2)L._rgan and G.Johansson,Anal.Chim.Acta.,1981,

125,45-53

(3)C.Preininger,Mikrochim.Acta,1999,130:209-214

(4)T.N.Shekhovtsova,S.V.Chemetskaya,Anal.Lett.,

1994,27(15)2883-2898

(5)Amine A.,Cremisini C.,Palleschi G.,Mikrochim Acta,

1995,121,183-190

the invention aims to provide a sensitive mercury ion detection strip based on the enzyme inhibition reaction and capillary action principle, which can directly detect a liquid sample, and the stability and the repeatability of the detection strip can meet the requirements of quantitative analysis.

The technical scheme of the invention is realized by the following modes: FIG. 1 is a schematic illustration of such a test strip. In the figure, a is a polyester film carrier, b is a reaction zone, and the reaction zone consists of 1 and 3 films. 1 is cellulose acetate film, and a certain amount of urease is adsorbed and fixed on the surface contacting with 3. 3 is a piece of precision pH test paper, on which a certain amount of urea and additive trehalose or dextran are adsorbed in advance. The reaction area is sealed by viscous transparent plastic 4, and a small hole 2 with the diameter of 1-1.5mm is reserved on the viscous transparent plastic on one side of the cellulose acetate membrane as a sample inlet. When the test strip is used, the test strip is inserted into a liquid sample, the solution is rapidly diffused and soaked in the cellulose acetate film through the sample inlet due to the capillary action of the cellulose acetate film, a large-size matrix in the solution is filtered by the cellulose acetate film and cannot enter a reaction area, and small-molecular inorganic or organic mercury enters the reaction area to be combined with a sulfhydryl group on urease, so that the activity of the enzyme is inhibited. The solution diffused to the edge of the cellulose acetate membrane permeates into the capillary of the pH test paper,then the urea adsorbed on the pH test paper is dissolved out by diffusing the urea from the edge to the center, and the dissolved urea is diffused to a cellulose acetate membrane and is catalyzed and hydrolyzed by urease in the following modes: OH^-the yield of (a) is inversely proportional to the degree to which urease is inhibited. Since urea is firstly separated out from the edge of the pH test paper, OH is formed^-Firstly, the pH test paper is generated at the edge, so that the periphery of the pH test paper is firstly blue, and the phenomenon of yellow spots of blue ring sleeves is formed. FIG. 2 is photographs taken 11 minutes, 13 minutes, and 14 minutes after the test strip was inserted into the sample solution, respectively, and numbered A, B, C in that order. As can be seen from FIG. 2, the blue ring gradually expanded toward the center and the yellow stain gradually shrunk as the reaction proceeded. The reaction area is completely disappeared to be used as a reaction end point, and the time from the insertion of the test strip into the sample to the reaction end point is in positive correlation with the content of mercury in the sample. According to the color reaction time, the content of the mercury ions in the sample can be obtained from a pre-drawn time-concentration curveAmount of the compound (A).

Table 1 shows the comparison between the present invention and conventional spectroscopic methods (cold vapor atomic absorption spectroscopy, CV-AAS; cold vapor atomic fluorescence spectroscopy, CV-AFS), and it can be seen through the comparison that the present invention is simple in operation, easy to popularize, and can complement the spectroscopic methods to effectively monitor the mercury pollution condition in the environmental water sample on site.

In the process of completing the invention, the main indexes of the test strip are tested repeatedly. The test result shows that the pH range of the test strip is 6.5-7.6, and the temperature range is 25-35 ℃. Under optimized experimental conditions, the detection strip is used for detecting Hg in an aqueous solution²⁺The detection limit can reach 0.2ng/ml, the detection range is 0.2-200ng/ml, and the RSD is less than or equal to 10 percent. The detection results of methyl mercury and ethyl mercury are similar to those of inorganic mercury, and^pb2+、Cu²⁺、Cd²⁺、Zn²⁺、Ni²⁺and the common heavy metal ions have no obvious interference on detection. The experiment of adding drinking water and natural water shows that the matrix in the water sample has no obvious influence on the measurement of the detection strip.

TABLE 1 comparison of the present invention with conventional spectral analysis methods

The technical skill of the detection limit selective field detection capability requires that the pretreatment requires analysis of the speed Cv-AAs 0.02ng/ml good-difference high-height fast Cv-AFs 0.001ng/ml good-difference high-height fast method 0.2ng/ml better,none or little low and fast

Claims

1. A test strip for qualitative and quantitative analysis of mercury compound by enzyme inhibition chromogenic reaction features that the edge of reaction region is first developed in ring form and then developed to expand toward center.

2. The test strip of claim 1, wherein the reaction zone has adsorbed thereto: urease and urea.

3. The test strip according to claim 1, wherein the reaction region is sealed with an adhesive transparent plastic, and a small hole (2) of 1 to 1.5mm is left in the adhesive transparent plastic in contact with the membrane (1) at a position corresponding to the center of the membrane (1).

4. The strip according to claim 1, wherein trehalose or dextran is added as an additive to the precision pH paper (3) to provide uniform color development and distinct color margin.