Two. background technology: the toxicity of cadmium is very big, can accumulate in human body in kidney, causes the changes of function of urinary system.The safe concentration of cadmium dialogue silver carp is 0.014mg/L.When containing cadmium among the farmland irrigating water, can cause field-crop to pollute above 0.007mg/L.The content of cadmium is lower than 1 μ g/L in most fresh water.The main pollution source of cadmium is in the waste water of industry such as plating, mining, smelting, battery, dyestuff and chemical industry discharging.
At present, in the water there be traditional assay method of cadmium content: atomic absorption spectrophotometry, graphite furnace atomic absorption spectrometry and dithizone spectrophotometric method.The basic step of dithizone spectrophotometric method is:
1. sample pretreatment
Accurately measure an amount of sample and put into the 250mL separating funnel, add water and be supplemented to 100mL, drip 3 0.1% thymol blue indicator solutions again, be adjusted to NaOH solution or HCL solution and stable yellow just occurs.
2. colour developing extraction
Add 50% potassium sodium tartrate solution 1mL to the test solution that places the 250mL separating funnel, 40%NaOH-1%KCN solution 5mL and 20% oxammonium hydrochloride solution 1mL.All shake up behind a kind of reagent of every adding.
The dithizone chloroform soln 15mL of adding 0.01% vibrated 1 minute immediately, and opened the venting of separating funnel plug.The methenyl choloride layer is put into the separating funnel that second cover has filled 2% tartaric acid solution 25mL, again with the solution in the 10mL methenyl choloride washing first cover separating funnel, after the washing methenyl choloride is incorporated in the second cover separating funnel, and shaken immediately 2 minutes, discard the methenyl choloride layer then.
Add the 5mL methenyl choloride in the second cover separating funnel, shook 1 minute, discard the methenyl choloride layer, it is careful more good more to separate.Add 20% oxammonium hydrochloride solution 0.25mL and 0.002% dithizone chloroform soln 15mL then in order, and 40%NaOH-0.05%KCN solution 5mL, extraction 1 minute shaken immediately.After 5 minutes, the methenyl choloride layer is filtered in the 30mm cuvette by clean absorbent cotton.
3. measure
Behind the completing steps 2, be reference immediately with the methenyl choloride, measure the absorbance of above-mentioned methenyl choloride layer at 518nm wavelength place, after the deduction blank test absorbance, find cadmium content from typical curve.
Blank test is to replace sample with 100mL distilled water, handles and measures by above-mentioned steps.
4. the drafting of typical curve
In a series of 250mL separating funnels, add 1.00 μ g/mL cadmium standard solution 0mL, 0.25mL, 0.50mL, 1.00mL, 2.00mL, 3.00mL, 5.00mL respectively, respectively add an amount of distilled water again and be supplemented to 100mL, drip 0.1% thymol blue indicator solution, be adjusted to the NaOH solution of 0.1moL/L and stable color just occurs.Below extract and measure by above-mentioned sample measurement step, and draw through the absorbance of blank correction typical curve to cadmium content.
The problem that the dithizone spectrophotometric method exists:
(1) potassium cyanide KCN is an extremely toxic substance, methenyl choloride, and the use of poisonous and harmful reagent such as cadmium standard solution can cause serious secondary pollution.
(2) operating process such as drafting of extraction and typical curve are tediously long, loaded down with trivial details, and labour intensity is big.
(3) need with the Instrument measuring absorbance and with formula calculating concentration value, high to the operator quality requirement, the testing cost costliness.
(4) after the NaOH-KCN solution preparation, could use after must placing a couple of days, cause the test duration prolongation.
(5) dithizone reagent must be through purification, complex steps, and need to consume a large amount of noxious material chloroform solns.
(6) the dithizone cadmium complex that reaction generates in test is very unstable, must extract rapidly and measuring operation.
(7) in test, disturbing factor is many, deals with improperly and causes measured data inaccurate easily, and error is big.
Three. the utility model content:
The utility model purpose:, make a kind of easy to carry, Cadmium Colorimetric Determination Tube of using simple and fast at disadvantages of background technology.
Technical solutions of the utility model:
A kind of Cadmium Colorimetric Determination Tube, be vacuum sealing tube, contain the uniform cross section glass tube of end sealing, the opening part of glass tube is communicated with transition section with the kapillary of end sealing, cadmium determination solution is housed in glass tube, measures height H 1 and glass tube uniform cross section the leave a blank height H of liquid in glass tube
2Ratio be H
1: H
2=1: 3~15.
Cadmium determination solution in the glass tube, with the unit volume is example, contain 0.05% diazoamino azobenzene compound 5~30 unit volumes, pH damping fluid 0~50 unit volume, surfactant 5~30 unit volumes, mixed preparing forms, and measures the raising or the reduction of each components and concentration in the liquid, and its volume is corresponding to be dwindled or increase.
In glass tube, measure the height H of liquid
1With the glass tube uniform cross section height H of leaving a blank
2Ratio be H
1: H
2=1: 7~10.
Positive beneficial effect of the present utility model is:
1. the utility model is with the detection technique commercialization, and commercialization is loaded on the mensuration fluid-tight for preparing in the glass tube with vacuum, can directly use.Only need during operation to fracture in the water sample to be measured capillary tube segment of test tube makes in the water sample automatic ration tail pipe to be measured and measures liquid generation metachromasia, just can draw cadmium content more accurately with the contrast of standard color range behind the colour stable.Need not be when each mensuration preparing standard solution, reagent, can simplify the detection step greatly, save minute, reduce workload, reduce labor intensity.
2. it is reasonable that the utility model is measured formula of liquid, advanced technology, and stable performance is used simple.Adopt standard sample liquid to react with it in advance, constant color forms permanent colour code, and encapsulation forms the contrast color range, carries out the scene and detects, and need not to prepare other any reagent, and testing result accurately and reliably.The standard colour code can be made by standard color range pipe of the present utility model and form, also can be, or the colored printing cardboard, or the colored plastic rod by the computer color atlas, or other physical medium material such as stained glass goods forms, and uses very convenient.
3. compare with the method for traditional dithizone spectrophotometry cadmium content, the utility model has reduced measuring process, has accelerated finding speed.
4. to measure the chromogenic reaction of liquid and determinand cadmium be to carry out automatically under given conditions the glass tube with vacuum to the utility model, can effectively avoid accidental error and personal error, testing result meets the requirement of water analysis error precision accurately and reliably, and detection limit meets national potable water requirement standard.
The utility model carry, easy to use, measure simple fast, accurately, the holding time is long.The on-the-spot detection do not need the miscellaneous equipment instrument, saves human and material resources greatly, reduces integrated cost.The utility model is easy to promotion and implementation, has good social and economic benefit.
The utility model testing tube and dithizone spectrophotometric method data comparison sheet:
Five. embodiment
Embodiment one:
Make the series standard colour code that detects cadmium content in advance, form color range.For example make 9 the color range pipes of standard colour code that detect cadmium content in the water quality, cadmium content is respectively 0.0mg/L, 0.005mg/L, 0.01mg/L, 0.02mg/L, 0.04mg/L, 0.06mg/L, 0.08mg/L, 0.10mg/L, the standard colour code of 0.20mg/L.At first get 0.05% 4-nitro diazoamino azobenzene 25mL, borax-NaOH damping fluid 50mL, Tritonx-100 surfactant 13mL, be mixed and made into mensuration liquid, making cadmium content then respectively is 0.0mg/L, 0.005mg/L, 0.01mg/L, 0.02mg/L, 0.04mg/L, 0.06mg/L, 0.08mg/L, 0.10mg/L, 0.20mg/L 9 kinds of normal concentration cadmium aqueous solution, will measure liquid and various normal concentration cadmium aqueous solution pours into reaction solution in 9 charomatrons respectively in 1: 7 ratio, and constant color, seal charomatron then, form non-fading serial color range standard colors mark pipe.The mensuration liquid concentration of production standard color range pipe is identical with the mensuration liquid concentration of supporting mensuration pipe, the ratio of mensuration liquid and normal concentration cadmium aqueous solution volume when measuring the corresponding production standard color range of the ratio pipe of liquid volume and the volume of leaving a blank in the pipe.Measure formula of liquid not simultaneously, the corresponding standard colour code of making, the color range of formation is also different.Only use the compound method of method description standard colour code for example at this.
Measure the pipe implementation method: referring to Fig. 1,1 is the uniform cross section glass tube with vacuum among the figure, and 2 is capillary tube segment, and 3 is cadmium determination solution.H
1For measuring liquid height, H
2The uniform cross section glass tube with vacuum is left a blank highly.The mensuration liquid of the corresponding preparation standard colour code of present embodiment, promptly measuring liquid and aqueous solution volume ratio to be measured is 1: 7.6.5 millimeters of uniform cross section vacuum glass external diameter of pipe, 11.6 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1.2 centimetres, the height H of leaving a blank
2Be 8.4 centimetres, capillary tube segment length is 2.0 centimetres.
During use, the capillary tube segment of measuring pipe is immersed in the water sample to be measured, capillary tube segment fractures, be filled the uniform cross section glass tube with vacuum pipeline section of leaving a blank etc. water sample to be measured, take out to be inverted repeatedly and mix, make it fully to carry out chromogenic reaction, contrast with the standard colour code behind about 1~2 minute colour stable, the pairing cadmium concentration numerical value of the colour code that is near the mark most is the cadmium content that records, if measure the pipe color between two standard colour codes, then gets its mean value.
Cadmium Colorimetric Determination Tube of the present invention is measured formula of liquid: represent with unit volume, contain 0.05% 4-nitro diazoamino azobenzene 25 unit volumes, borax-NaOH damping fluid 50 unit volumes, Tritonx-100 surfactant 13 unit volumes.
Embodiment two: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 7 millimeters in the present embodiment, 7.1 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1.4 centimetres, the height H of leaving a blank
2Be 4.2 centimetres, capillary tube segment length is 1.5 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain 0.05% 4-nitro diazoamino azobenzene 5 unit volumes, borax-NaOH damping fluid 23 unit volumes, Tritonx-100 surfactant 13 unit volumes.
Embodiment three: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.The using method of standard colors target method for making, the method for making of measuring pipe and testing tube no longer is described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 6.5 millimeters in the present embodiment, 10.8 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1 centimetre, the height H of leaving a blank
2Be 8 centimetres, capillary tube segment length is 1.8 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain 0.05% 4-nitro diazoamino azobenzene 14 unit volumes, borax-NaOH damping fluid 50 unit volumes, Tritonx-100 surfactant 21 unit volumes.
Embodiment four: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 7 millimeters in the present embodiment, 19.3 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1.1 centimetres, the height H of leaving a blank
2Be 16.5 centimetres, capillary tube segment length is 1.7 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain nitronaphthalene diazo aminobenzene-4-azobenzene 22 unit volumes of 0.05%, NH
3-NaOH damping fluid 36 unit volumes, Tritonx-100 surfactant 5 unit volumes.
Embodiment five: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 6.5 millimeters in the present embodiment, 13.8 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1.2 centimetres, the height H of leaving a blank
2Be 10.8 centimetres, capillary tube segment length is 1.8 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain nitronaphthalene diazo aminobenzene-4-azobenzene 30 unit volumes of 0.05%, NH
3-NaOH damping fluid 10 unit volumes, Tritonx-100 surfactant 25 unit volumes.
Embodiment six: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 6.5 millimeters in the present embodiment, 10.2 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1.2 centimetres, the height H of leaving a blank
2Be 7.2 centimetres, capillary tube segment length is 1.8 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain nitronaphthalene diazo aminobenzene-4-azobenzene 27 unit volumes of 0.05%, NH
3-NaOH damping fluid 16 unit volumes, Tritonx-100 surfactant 30 unit volumes.
Embodiment seven: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 7.0 millimeters in the present embodiment, 9.6 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1.0 centimetres, the height H of leaving a blank
2Be 7 centimetres, capillary tube segment length is 1.6 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain 0.05% p-sulfonic acid basic weight nitrogen aminoazabenzol 9 unit volumes, NaOH damping fluid 31 unit volumes, Tritonx-100 surfactant 17 unit volumes.
Embodiment eight: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 7 millimeters in the present embodiment, 12.8 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1 centimetre, the height H of leaving a blank
2Be 10 centimetres, capillary tube segment length is 1.8 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain 0.05% p-sulfonic acid basic weight nitrogen aminoazabenzol 18 unit volumes, NaOH damping fluid 45 unit volumes, Tritonx-100 surfactant 9 unit volumes.
Embodiment nine: referring to Fig. 1, numbering is identical with embodiment one among the figure, represents same meaning.Standard colors target method for making, the making of measuring pipe and using method no longer are described in detail with embodiment one.Difference is:
Uniform cross section glass tube with vacuum external diameter is 7 millimeters in the present embodiment, 12.8 centimetres of overall heights, the height H of mensuration liquid in the glass tube
1Be 1 centimetre, the height H of leaving a blank
2Be 10 centimetres, capillary tube segment length is 1.8 centimetres.
Cadmium Colorimetric Determination Tube in the present embodiment, the cadmium determination solution prescription is: represent with unit volume, contain 0.05% p-sulfonic acid basic weight nitrogen aminoazabenzol 7 unit volumes, NaOH damping fluid 39 unit volumes, Tritonx-100 surfactant 26 unit volumes.