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Alkaline precise pH test paper reusable by water washing, preparation method and application thereof

A ph test paper and reaction technology, which is applied in the fields of chemical reaction of materials, material analysis by observing the effect on chemical indicators, organic chemistry, etc. , to achieve the effect of intuitive and reliable test results, good reproducibility and strong tolerance

Active Publication Date: 2019-01-18
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the test paper method is convenient and quick to detect pH, the commonly used pH test paper still has the disadvantages that it cannot be recycled and is easily affected by the laboratory gas atmosphere.

Method used

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  • Alkaline precise pH test paper reusable by water washing, preparation method and application thereof
  • Alkaline precise pH test paper reusable by water washing, preparation method and application thereof
  • Alkaline precise pH test paper reusable by water washing, preparation method and application thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] Synthesize 4'-p-hydroxyazophenyl-2,2':6'2"-terpyridine at first, add to 170ml CH 3 Add 5g of 2-acetylpyridine and 3.17g of p-nitrobenzaldehyde to OH, add 15ml of 15% KOH aqueous solution and 160ml of NH 4 OH, the system was stirred at room temperature for 3 days. A dark red precipitate was obtained by suction filtration, which was washed three times with distilled water and cold methanol respectively. The filtered solid was dissolved in ethyl acetate with 1% NaHCO 3 After two-phase extraction of the aqueous solution for one time, the obtained organic phase was washed with anhydrous NaSO 4 Dry, CH 3 CH 2 OH recrystallization gave 4'-nitro-2,2':6'2"-terpyridine molecule with a yield of 34%.

[0043] 0.46g of the above-mentioned synthesized 4'-nitro-2,2':6'2"-terpyridine and SnCl 2 1.536 g was added into 12 ml of concentrated HCl and heated at 80°C for 8 hours. After cooling to room temperature, the residual solid powder was obtained by suction filtration, which wa...

Embodiment 2

[0047] Color change of the probe to alkalinity.

[0048] Weigh 10.84 mg of 4'-p-hydroxyazophenyl-2,2':6'2"-terpyridine synthesized in Example 1 and dissolve it in 20 ml of DMSO. After the solution is uniform and stable, pipette 1 ml of the above solution Dilute to 50ml to obtain light yellow probe mother solution.

[0049] Prepare 250ml of 0.1mol / L NaOH aqueous solution, serially dilute and use a pH meter to accurately and quantitatively prepare standard NaOH aqueous solution with pH 7-13, pipette 4ml of the probe mother solution into multiple glass vials, and pipette 67ul of standard solutions with different pH Mix it with the probe mother solution, measure the UV-visible absorption curve of the detection solution under different pH, and take pictures of the color changes in different vials.

[0050] from figure 2 a UV-Vis absorption curve can be seen, and OH - For the interacting probe molecule, the absorption peak has a red shift from 372nm to 523nm, corresponding to th...

Embodiment 3

[0052] The preparation process of the probe mother solution is the same as in Example 2.

[0053] Prepare NaBr, NaF, NaCl, NaH with a concentration of 0.012mol / L respectively 2 PO 4 , Na 2 HPO 4 , Na 3 PO 4 , Na 2 SO 4 For the aqueous solution, pipette 67ul of different salt solutions to mix with the mother solution, measure the UV-visible absorption curves of different detection solutions and take pictures of the color changes in different vials.

[0054] from image 3 It can be seen from the UV-visible absorption curve of a that the probe molecules can also respond to different Brewster base aqueous solutions that can dissociate hydroxide ions, making the absorption peak of the molecules red-shift from 372nm to 523nm. The depth of the color change in the visible range is related to the dissociation constant of the salt solution, that is, the pH of the solution, where pka 3 Larger Na 3 PO 4 The solution is the most alkaline, and the color change of the solution is ...

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Abstract

The invention relates to alkaline precise pH test paper reusable by water washing, a preparation method and an application thereof, belongs to the technical field of colorimetric analysis and detection, and provides a compound 4'-p-hydroxyazophenyl-2,2':6'2''-terpyridine shown in a formula I which is described in the specification, and a preparation method thereof. The preparation method comprisesthe following steps of: firstly preparing and obtaining 4'-nitro-2,2':6'2''-terpyridine, then using the 4'-nitro-2,2':6'2''-terpyridine to prepare and obtain 4'-amino-2,2':6'2''-terpyridine, and thenreacting with phenol to obtain 4'-p-hydroxyazophenyl-2,2':6'2''-terpyridine. The compound shown in the formula I is used as a probe molecule to prepare the alkaline precise pH test paper which can beused for detecting the change of an aqueous phase in the pH range 11-14.

Description

technical field [0001] The invention belongs to the technical field of colorimetric analysis and detection, and in particular relates to an alkaline precision pH test paper which can be reused through washing and its preparation method and application. Background technique [0002] pH is an important basic concept in electrochemistry, and it is also a widely used chemical index of solutions. Because the definition includes the activity of a single ion, and the thermodynamic method can only measure the average activity of the electrolyte (that is, the average activity of positive and negative ions), it is not a physical quantity that can be directly measured. In solution chemistry, as an important indicator for detecting the acidity and alkalinity of a solution, the pH value often requires a fixed detection standard and a galvanic electrode support based on potentiometric analysis. The appearance of pH test paper provides a more convenient and intuitive way of thinking for p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07D213/42G01N21/80
CPCC07D213/42G01N21/80
Inventor 郝京诚董川
Owner SHANDONG UNIV
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