METHOD OF OBTAINING STANDARD SAMPLES FOR MEASUREMENT OF ZETA POTENTIAL VALUES OF PARTICLES OF COLLOIDAL SYSTEMS USING OPTICAL METHODS Russian patent published in 2023 - IPC G01N1/28 

FIELD: chemistry.

SUBSTANCE: invention relates to the methods of preparing standard samples for measuring the zeta potential of particles in colloidal systems and can be used to improve the efficiency of laboratory control services in chemical, petrochemical, clinical and pharmaceutical laboratories, as well as water purification and water treatment services. A method of obtaining standard samples for measuring the zeta potential of particles of colloidal systems by optical methods includes the preparation of low-concentrated aqueous solutions of sulfur-containing amino acids, such as L-cysteine, to obtain standards with a value in the positive region of the electrokinetic (zeta) potential, and N-acetyl-L-cysteine for obtaining standards with a value in the negative region of the electrokinetic (zeta) potential; mixing the resulting solutions of sulfur-containing amino acids with a solution of silver acetate or nitrate, respectively, in a molar ratio of 1.25 or equimolar, respectively, so that the concentration of sulfur-containing amino acids in the mixture is in the range of 0.75–3.00 mM, depending on the required value of the zeta potential of the particles; keeping the mixture in a place protected from light at a temperature of 18–28° C for 48–72 hours to form standard samples with the required values of the zeta potential of particles. Additionally, low-concentration aqueous solutions of sulfur-containing amino acids are mixed with a solution of oxalic acid based on deionized water so that the concentration of oxalic acid is in the range of 0.08–0.19 mM. Immediately before measurements, a solution of sodium chloride in an amount equimolar with oxalic acid is added to the standard sample for additional stabilization.

EFFECT: development of a method of producing standard samples characterized by a number of values above 70 mV in absolute value with a relative standard deviation of zeta potential values of not more than 10%.

2 cl, 4 dwg, 1 tbl