5 results about "Phenolphthalein" patented technology

This application provides a continuous titration method for the sulfuric acid and ammonium nitrate content of silicon etching solution. The continuous titration method includes the following steps: weigh m grams of silicon etching solution sample into a sample bottle, add phenolphthalein indicator, titrate with a first sodium hydroxide standard solution of concentration C1 until a pink color is achieved, and record the volume consumed V1. Calculate the sulfuric acid content. Add neutral formaldehyde solution to the same solution and let it stand for a first preset time to generate a free acid solution. Continue titrating the free acid solution with a second sodium hydroxide standard solution of concentration C2 until the solution turns pink. Gently heat the solution to a preset temperature and maintain this temperature for a second preset time. If the pink color persists, the titration endpoint is determined, and the volume consumed V2 is recorded. Calculate the ammonium nitrate content. This method achieves continuous titration of two components with a single sample, eliminates mutual interference between components, optimizes the endpoint determination method, and thus achieves a simple operation, high accuracy, low sample consumption, and high detection efficiency.

The present invention provides a cleaning composition containing alkaline electrolyzed water, which facilitates the production of a diluted solution having a predetermined pH. [Solution] A cleaning composition is provided which contains bromothymol blue, thymol blue, or phenolphthalein as a pH indicator, and alkaline electrolyzed water having a pH of 12 or higher.

The invention relates to the technical field of environmental protection, in particular to a treatment process of tussah soda boiling wastewater, which comprises the following steps: step 1, burning rice husks, putting the rice husks into an adsorption column after burning, pumping soda boiling wastewater to soak the adsorption column, flowing out of the adsorption column, and enriching in a primary treatment storage tank to obtain a primary recycled water body; measuring the pH and the protein content of the primary recycled water body in the storage tank; step 2, adding phenolphthalein polyarylether sulfone immobilized protease into the primary recycled water body in the step 1 for enzymolysis adsorption, and filtering to obtain polyarylether sulfone particles adsorbed with sericin protein enzymolysis peptide and secondary filtered wastewater; and step 3, adding sodium carbonate or sodium hydroxide into the secondary filtered wastewater in the step 2 to adjust the pH value, pumping the wastewater back to the cocoon cooking pool for secondary tussah alkali cooking degumming, and recovering a solid mixture of rice hull ash and coarse sericin.

The invention belongs to the technical field of chemical detection, and provides a method for detecting beta-cyclodextrin, which comprises the following steps: raising the temperature of beta-CD-containing feed liquid to be greater than or equal to 65 DEG C and less than 85 DEG C, inclusion phenolphthalein under a heat preservation condition, and then detecting the color development degree in an alkaline environment. According to the method, the detection range is greatly widened, tedious dilution is not needed, the operation is simplified, the efficiency is improved, and errors introduced in the dilution process are avoided; the method can be directly applied to detection of common high-concentration samples in industrial production.

The invention provides an online analysis method of primary loop boric acid, and belongs to the technical field of boric acid detection. The method comprises the following steps: firstly, diluting a water sample with demineralized water, dropwise adding a methyl red indicator, and carrying out acid solution titration; when acid solution titration reaches a first end point, mannitol and phenolphthalein indicators are added for alkaline solution titration, and when acid solution titration reaches a second end point, a C alkaline solution and a V alkaline solution are recorded; and finally, calculating the concentration of boric acid according to the sampling amount V0 of the water sample, the C alkali solution and the V alkali solution. The two indicators are respectively used in the two continuous titration processes, the indicator added for the first time can indicate the arrival of the first titration end point, and the indicator added for the second time does not interfere with the arrival of the second titration end point indicated by the indicator for the second time. According to the method, for judging the titration end point of methyl red, the design of double light source detection is adopted, and the titration end point of which the pH value is equal to 5.2 + / -0.2 is determined by calculating the absorbance value of the double light sources.