Embodiment
The present invention selects benzoic acid and rhodamine B to make the developer of uranium (VI), studies the chromogenic reaction of itself and uranium (VI), inquires into the top condition of reaction, records the content of trace uranium (VI), obtains better effects.Reaction mechanism is as follows:
1.1 key instrument and equipment
The key instrument, the equipment that use in the test are as shown in table 1.
Table 1 test key instrument and equipment
The instrument title |
Model |
Manufacturer |
Fluorospectrophotometer |
?LS55 |
U.S. PE company |
Acidometer |
?DOS-11A |
Chengdu Noah's ark scientific and technological development company |
Electronic balance |
?FA604A |
The triumphant grand company limited already in Beijing |
The ultrasonic cleaning instrument |
?KQ2200E |
Kunshan Ultrasonic Instruments Co., Ltd. |
1.2 main agents
Medicine used in the present invention sees table 2 for details.
Table 2 main agents
Nomenclature of drug |
Type |
Manufacturer |
Chemical formula |
Uranyl nitrate |
Analyze pure |
Made in China |
?UO2(NO3)2·6H2O |
Uranium acetate |
Analyze pure |
Made in China |
?UO2(CH3CO2)·2H2O |
Benzoic acid |
Analyze pure |
Dragon chemical industry examination factory of Chengdu section |
?C7H6O2 |
Rhodamine B |
Analyze pure |
Close sour manufacturing plant of Tianjin section |
?C28H31CLN2O3 |
NaOH |
Analyze pure |
Dragon chemical industry examination factory of Chengdu section |
?NaOH |
Nitric acid |
Analyze pure |
Dragon chemical industry examination factory of Chengdu section |
?HNO3 |
1.3 experimental procedure
1.3.1 experimental solutions preparation
1. the preparation of uranyl nitrate
Accurately take by weighing the uranyl nitrate of 50.133mg with 1,000,000/balance (0.001mg), pour in the 50mL beaker of cleaning in advance, add about 20mL distilled water, solution is moved in the volumetric flask of 100mL, and with distilled water diluting to scale, be mixed with 0.9982 * 10
-4MolL
-1Preserve.
2. the preparation of uranium acetate solution
Accurately take by weighing the uranium acetate of 46.507mg with 1,000,000/balance (0.001mg), pour in the 50mL beaker of cleaning in advance, add about 20mL distilled water, solution is moved in the volumetric flask of 100mL, and with distilled water diluting to scale, 1.0964 * 10
-4MolL
-1Preserve.
3. the preparation of benzoic acid solution
Accurately take by weighing the benzoic acid of 12.669mg with 1,000,000/balance (0.001mg), pour in the 50mL beaker of cleaning in advance, add about 20mL distilled water, solution is moved in the volumetric flask of 100mL, and with distilled water diluting to scale, 1.011 * 10
-4MolL
-1Preserve.
4. the preparation of rhodamine B solution
Accurately take by weighing the rhodamine B of 45.101mg with 1,000,000/balance (0.001mg), pour in the 50mL beaker of cleaning in advance, add about 20mL distilled water, solution is moved in the volumetric flask of 100mL, and with distilled water diluting to scale, 0.9415 * 10
-4MolL
-1Preserve.
5. acid-base solution preparation (adjusting pH value)
(1) NaOH: accurately take by weighing 4.0g NaOH, pour clean beaker into, add the suitable quantity of water dilution, the solution after will diluting again joins in the volumetric flask of 100mL, adds water to scale, shakes up to get final product.Concentration is molL-1.Waiting needs the time spent, is diluted to desired concn.
(2) nitric acid: accurately take by weighing the red fuming nitric acid (RFNA) of 9.69g65%, pour clean beaker into, add the suitable quantity of water dilution, the solution after will diluting again joins in the volumetric flask of 100mL, adds water to scale, shakes up to get final product.Concentration is molL-1.Waiting needs the time spent, is diluted to desired concn.
1.3.2 the selection of developer
1. the complex of uranium is selected
At excitation wavelength 310nm, emission wavelength 596nm excites slit 5.0 to uranyl nitrate, benzoic acid solution, rhodamine B solution, and the emission slit is measured fluorescence intensity 3.0 times, obtains the results are shown in Table 3.As can be seen from Table 3: the uranium individualism does not have fluorescence, and mixing with benzoic acid does not have fluorescence yet.Uranyl nitrate has stronger fluorescence after the mixing of benzoic acid and rhodamine B.
The Different Complex fluorescence intensity table of table 3 uranium
The fluorescence intensity of table 4 different mixture ratio
2. benzoic acid and rhodamine B match ratio are selected
At excitation wave 310nm, transmitted wave 596nm excites slit 5.0, and emission slit 3.0 times benzoic acid and rhodamine B measured in solution fluorescence intensities to different proportionings obtain result such as table 4.Can draw by last table 4 result: benzoic acid and rhodamine B the two than being that 1: 1 o'clock fluorescence is the strongest.
1.3.3 the best excites the selection with emission wavelength and slit
1. the best selection that excites with emission wavelength
With uranium and benzoic acid and rhodamine B three ratio is that 1: 1: 1 mixed liquor is made Fig. 1, and as can be seen from Figure 1 at exciting light during at the 260nm place, resulting exciting light spectrogram intensity is moderate, and is disturbed lessly, and intensity is bigger.Between 550nm-610nm, promptly there is big emission wavelength at the 575nm place.
2. the selection of slit
With uranium and benzoic acid and rhodamine B three mol ratio is 1: 1: 1 mixed liquor, with the optical excitation of 260nm, selects difference to excite and launches slit and do the fluorescence spectrum mapping, as shown in Figure 2.As seen exciting slit from Fig. 2: 5.0nm, the emission slit: 3.0 exciting light spectrogram intensity are moderate, and disturbed lessly, and the peak type is level and smooth, herein best results.
1.3.4 system acidity is selected
1: 1 mixed liquor of benzoic acid and rhodamine B is at excitation wave 260nm, and transmitted wave 575nm excites slit 5.0, and the emission slit is measured different pH fluorescence intensities for 3.0 times, obtains result such as table 5.As can be seen from Table 5, adopt nitric acid as medium, mixed liquor is the fluorescence intensity maximum when pH=4.
The different pH values of table 5 are the fluorescence intensity of mixed liquor down
PH |
Mixed liquor (1: 1) |
2.0 |
159.723 |
4.0 |
184.699 |
6.0 |
184.026 |
8.0 |
160.220 |
1.3.5 the influence of coexisting ion
The fluorescence intensity that table 6 different ions is disturbed
Ion |
?Na
+ |
K
+ |
Ca
2+ |
Pb
2+ |
Ni
2+ |
Cu
2+ |
Mg
2+ |
Al
3+ |
Co
2+ |
Hg
+ |
Ag
+ |
Fe
3+ |
NO
3 |
Intensity (int) |
?86 |
144 |
182 |
183 |
187 |
180 |
190 |
187 |
175 |
185 |
186 |
56 |
183 |
Can find out that from table 6 add common interfering ion in the mixed liquor that uranium (VI) exists, the result shows Ca
2+, Pb
2+, Ni
2+, Zn
2+, Mg
2+, Al
3+, Co
2+, Hg
+, Ag
+, NO
3 -Deng very little to its fluorescence influence in the milligram level.Na
+, K
+Uranium solution there is the effect of weakening.Fe
3+Interference effect is also arranged, but Fe
3+Allowance can reach 100 times, can add EDTA and shelter, can eliminate interference.
1.3.6 stability test
Compound concentration is 2.4 * 10
-7The uranium of mol/L (VI) solution is used excitation wave 260nm, and transmitted wave 575nm excites slit 5.0, and the emission slit is measured the different time fluorescence intensity 3.0 times, sees Table 7.
Fluorescence intensity under table 7 different time
Time (min) |
5 |
10 |
20 |
30 |
60 |
Intensity (int) |
254.14 |
253.80 |
254.70 |
254.65 |
253.64 |
As shown in Table 7, the intensity of solution is little with the variation of sweep time, and the complex of uranium (VI) is more stable.
1.3.7 lowest detection line
According to above-mentioned test condition.Original mixed liquid is diluted to 250 times respectively, 500 times, 1000 times, 2000 times, 5000 times, 10000 times.Uranium (VI) solution concentration is respectively 3.992 * 10
-7MolL
-1, 1.996 * 10
-7MolL
-1, 0.9982 * 10
-7MolL
-1, 0.4991 * 10
-7MolL
-1, 0.1996 * 10
-7MolL
-1, 0.9982 * 10
-8MolL
-1Record fluorescence intensity and see Table 8.
Table 8 dilution variable concentrations fluorescence intensity
Extension rate |
250 times |
500 times |
1000 times |
2000 times |
5000 times |
10000 times |
Fluorescence intensity |
355.51 |
196.5 |
106.71 |
55.24 |
21.28 |
?8.68 |
As can be seen from Table 8, the concentration of uranium (VI) detection lower limit is about 0.9982 * 10
-8MolL
-1
1.3.8 the drafting of typical curve
Get 6 10mL volumetric flasks, number 0-5 respectively.Get distilled water as blank solution, numbering 0.It is 1.996 * 10 that 1-5 adds concentration respectively
-7MolL
-1, 1.502 * 10
-7MolL
-1, 0.9982 * 10
-7MolL
-1, 0.4991 * 10
-7MolL
-1, 0.1996 * 10
-7MolL
-1The uranium mixed liquor, regulate pH=4, use excitation wavelength 260nm, emission wavelength 575nm excites slit 5.0nm, emission slit 3.0nm is mensuration down.Table sees 9 as a result.
The tabulation of table 9 typical curve
Numbering |
Concentration (mol/L10
-7)
|
Intensity |
Background value |
0 |
0 |
0.117 |
8.584 |
1 |
0.2 |
21.252 |
8.584 |
2 |
0.5 |
55.540 |
8.584 |
3 |
1.0 |
106.718 |
8.584 |
4 |
1.5 |
147.289 |
8.584 |
5 |
2.0 |
196.547 |
8.584 |
Make Fig. 3 by table 9; Linear equation is y=-4.505x
2+ 105.424x+0.0 degree of fitting is: 0.9988
1.3.9 the mensuration of sample
Adopt the pure uranium acetate of analysis to measure as sample.Uranium acetate concentration is formulated as: 2.1928 * 10
-7MolL
-1, 1.0964 * 10
-7MolL
-1, 0.5482 * 10
-7MolL
-1(add 1: 1 benzoic acid of equivalent and rhodamine B mixed liquor, and regulate pH=4), use excitation wave 260nm, transmitted wave 575nm excites slit 5.0nm, and emission slit 3.0nm is mensuration down, sees Table 10.
The tabulation of table 10 sample determination
The result who records as shown in Table 10 conforms to substantially with normative reference, and relative error is 3.6%.
2 conclusions
The solution of uranium (VI) does not have fluorescence, but behind the complex that forms with specical regent benzoic acid and rhodamine B hyperfluorescence is arranged, and can measure the content of uranium (VI) element with the fluorescent liquid method.Be that uranium (VI) can form stable coordination compound with benzoic acid and rhodamine B under 1: 1 the condition in benzoic acid and rhodamine B mol ratio.In nitric acid medium, be 4.0 o'clock to be the optimum acidity that complex fluorescent is analyzed at pH.The maximum excitation wavelength of the complex of uranium (VI) is 260nm, and emission wavelength is 575nm, excites and launch slit to be: 5.0nm and 3.0nm.
Should be understood that, for those of ordinary skills, can be improved according to the above description or conversion, and all these improvement and conversion all should belong to the protection domain of claims of the present invention.