CN-122017083-A - Method for quantifying key components of polycarboxylic acid water reducer and rapidly detecting water reduction rate based on liquid chromatography

CN122017083ACN 122017083 ACN122017083 ACN 122017083ACN-122017083-A

Abstract

The invention discloses a method for rapidly detecting key components of a polycarboxylic acid water reducer and water reducing rate based on liquid chromatography, belonging to the technical field of rapid detection of high-performance water reducers, the characteristic that the chemical components are easy to pass through polarity separation is utilized, and the concentration of key chemical components such as macromonomer, triterpenoid saponin and the like in the water reducer is quantitatively detected by adopting a liquid chromatography combined with an evaporative light scattering detection technology; by fitting a standard curve and establishing a regression equation of the concentration of the key components and the water reducing rate, the quick calculation of the water reducing rate of the water reducing agent is realized, and meanwhile, the quantitative detection and quality judgment of key components of the product are completed.

Inventors

GAO JIANQIANG
LI ZHIYUAN
FAN SHANZHI
TAO SHIHAO
YU SHANGRAN
Han Renbing
Zhen Zida

Assignees

兰州交通大学

Dates

Publication Date: 20260512
Application Date: 20260326

Claims (5)

1. The method for rapidly detecting the key component quantification and the water reduction rate of the polycarboxylic acid water reducer based on the liquid chromatography is characterized by comprising the following steps of: Step 1, preparing standard solutions, namely selecting white sugar, citric acid monohydrate, a large monomer, acrylic acid, triterpenoid saponin, sodium gluconate, sodium thiosulfate, sodium metabisulfite and sodium bisulphite as standard substances, and respectively preparing series mixed standard solutions with various concentrations; step2, standard curve fitting: 2.1 optimizing chromatographic conditions, namely setting liquid chromatography detection parameters, and optimizing mobile phase proportion, flow velocity, column temperature and detection wavelength by adopting an evaporative light scattering detector; 2.2 chromatographic detection and curve fitting, namely carrying out chromatographic analysis on the series of mixed standard solutions prepared in the step 1 one by utilizing optimized chromatographic conditions, taking the peak area (y) of each chromatographic peak of the target substance as an ordinate and the mass concentration (x) of the corresponding substance as an abscissa, and adopting a least square method to fit a working curve to obtain a standard curve equation and a linear range of each target substance; 2.3, confirming a standard curve equation of a large monomer, triterpenoid saponin and white sugar, ensuring that the linear correlation coefficient R2 is more than or equal to 0.996, and meeting the quantitative detection requirement; and 3, quantitatively detecting key components of the water reducer sample: 3.1, sample pretreatment, namely taking a polycarboxylic acid high-performance water reducer finished product sample, and preparing a sample solution meeting chromatographic detection requirements after dilution and filtration treatment; 3.2, sample chromatographic detection, namely carrying out chromatographic detection on a sample solution under the same chromatographic condition optimized in the step 2 to obtain an evaporative light scattering detector chromatogram of the finished water reducer; 3.3, calculating the concentration of the components, namely determining chromatographic peaks corresponding to the macromonomer and the triterpenoid saponin according to the sequence of peak time in the chromatogram, reading the peak areas of the chromatographic peaks, substituting the peak areas into a corresponding standard curve equation obtained by fitting in the step 2, and calculating the mass concentration of the macromonomer and the triterpenoid saponin in the finished water reducer; and 4, rapidly calculating the water reducing rate: 4.1 establishing a regression equation, namely fitting the measured data of the total concentration and the water reducing rate of the macromer and the triterpenoid saponin of a plurality of groups of water reducing agent samples according to a least square method, and establishing a regression equation of the water reducing rate (Y) and the total concentration (X) of the macromer and the triterpenoid saponin, wherein Y=1.098X+ 6.8588 (R2=0.9984), Y is the water reducing rate (%), and X is the total concentration (%) of the macromer and the triterpenoid saponin; 4.2, calculating the water reducing rate, namely substituting the total concentration of the macromer and the triterpenoid saponin in the finished water reducing agent calculated in the step 3 into the regression equation, and rapidly calculating to obtain the water reducing rate of the finished water reducing agent; And 4.3, judging the quality of the water reducer product by combining quantitative detection results of the macromonomer and the triterpenoid saponin and the calculated water reduction rate and comparing the component content and the water reduction rate reference index established when the product enters the field for the first time.
2. The method for rapidly detecting the key component quantification and the water reduction rate of the polycarboxylic acid water reducer based on the liquid chromatography as claimed in claim 1 is characterized in that the reliability verification of the detection method is carried out after the step 3, and the method comprises the steps of adding standard recovery rate test and repeatability and stability test; Adding standard substances with different concentrations into a finished water reducer sample, detecting under the same chromatographic condition, calculating the standard adding recovery rate, verifying the accuracy of a detection method, and controlling the standard adding recovery rate to be 90.2% -110.8%; And (3) testing repeatability and stability, namely repeatedly testing the same water reducer sample for multiple times under the same chromatographic condition in the same day and on different working days, calculating Relative Standard Deviation (RSD), and verifying the repeatability and stability of the testing method, wherein the relative standard deviation is required to be less than or equal to 3.6%.
3. The method for rapidly detecting key components of the polycarboxylic acid water reducer based on the liquid chromatography, which is disclosed by claim 1, is characterized in that the liquid chromatography condition after optimization in the step 2 is that a C18 reversed phase chromatographic column is selected as a chromatographic column, a mobile phase is methanol-water solution, a gradient elution mode is adopted, the flow rate is controlled to be 0.8-1.2 mL/min, the column temperature is set to be 30-35 ℃, the temperature of a drift tube of an evaporative light scattering detector is 80-90 ℃, and the flow rate of carrier gas is 2.0-2.5L/min.
4. The method for rapidly detecting the key components of the polycarboxylic acid water reducer based on the liquid chromatography, which is disclosed by claim 1, is characterized in that the specific method for sample pretreatment in the step 3 is that 1mL of finished water reducer sample is taken, diluted to 100mL by distilled water, shaken uniformly and filtered by a 0.22 mu m filter membrane, and impurities are removed for later use.
5. The method for rapidly detecting the key component quantification and water reduction rate of the polycarboxylic acid water reducer based on the liquid chromatography according to claim 1, wherein the concentration of the series of mixed standard solutions in the step 1 is 5mg/L, 25mg/L, 50mg/L, 100mg/L, 250mg/L, 625mg/L, 1250mg/L and 2500mg/L in sequence.

Description

Method for quantifying key components of polycarboxylic acid water reducer and rapidly detecting water reduction rate based on liquid chromatography Technical Field The invention belongs to the technical field of rapid detection of high-performance water reducers, and particularly relates to a method for rapidly detecting key components of a polycarboxylic acid water reducer and water reduction rate based on liquid chromatography. Background Since the naphthalene-based and melamine-based high-efficiency water reducer is gradually popularized and applied in the 60 th century of 20 th, the concrete production and construction technology realizes the crossover development, and the performance improvement of the concrete material is also deeply bound with the technical progress of the water reducer. With the continuous improvement of the requirements of engineering construction on the performance of concrete, novel concrete such as high-performance concrete, self-compacting vibration-free concrete, fiber grouting concrete, underwater non-discrete concrete and the like are successfully developed successively and widely applied to key engineering such as three gorges dam, hangzhou bay cross-sea bridge, jinghu high-speed railway and the like, and the excellent performance of the novel concrete is not separated from the support of the high-performance water reducer. The polycarboxylic acid high-performance water reducer is used as a novel water reducer which is rapidly developed in recent years, has the remarkable advantages of strong cement dispersibility, high water reducing rate, small loss of concrete slump with time, wide cement adaptability and the like compared with the traditional lignin water reducer and naphthalene water reducer, has comprehensive properties far exceeding those of the traditional water reducer, is recognized as a third-generation water reducer, is a historical breakthrough in the development history of the water reducer, and becomes the main stream development direction of the concrete water reducer in the future. At present, the development of the polycarboxylic acid water reducer in China is still in the primary stage, the related research is started at the end of the 20 th century, engineering application is limited in recent years, but due to the excellent comprehensive performance, the polycarboxylic acid water reducer is widely focused and successfully applied to various key projects in industry, even in Japan with leading research and application in the field, the development process of the polycarboxylic acid water reducer is only over twenty years, the polycarboxylic acid high-performance water reducer is still in the continuous perfection and upgrading stage at present, the core component is a large monomer, and various small monocotyledonous small materials are grafted on carbon long chains such as acrylic acid and the like. At present, researchers at home and abroad develop a great deal of research work around the molecular structure, application performance and action mechanism of the polycarboxylate-type water reducer, but obvious short plates and technical blanks still exist in the field of product quality control. The existing detection standard mainly comprises performance detection, the quality of the water reducer is indirectly judged through a cement paste and concrete performance test, and the solid content is detected in an auxiliary mode to judge whether the polymer content reaches the standard or not. However, the quality of the polycarboxylic acid water reducer not only depends on the solid content and the water reduction rate, but also has critical effects on the water reduction effect, the concrete workability and the durability due to the key indexes such as the polymer content, the specific component composition and the double bond saturation rate, and the like, and the systematic research on the key indexes at home and abroad is recently reported, and the related detection technology is also deficient. In the actual engineering raw material quality control, the quality of the polycarboxylic acid water reducer cannot be comprehensively, accurately and efficiently judged only by means of solid content and water reduction rate detection, unqualified products are easy to flow into an engineering site, the concrete engineering quality and the durability of a structure are affected, meanwhile, the traditional concrete performance test is time-consuming and labor-consuming, the detection period is long, and the requirements of the engineering site on the rapid detection and daily monitoring of the quality of the water reducer cannot be met. Based on the action mechanism and molecular composition of the polycarboxylic acid water reducer, the chemical components of the polycarboxylic acid water reducer have the characteristic of easy polarity separation, and the quantitative detection of various chemical components of the polycarboxylic acid water reducer can be reali