7 results about "Theoretical plate" patented technology

The invention relates to an overlapped chromatographic peak positioning and splitting method and system based on a numerical stable function. The method comprises the following steps: de-noising chromatographic data and correcting a baseline; calculating a second derivative by using SG filtering, grouping continuous points according to a negative threshold value, and determining an initial position of each peak by using a second-order minimum value; establishing a peak function of bidirectional exponential correction by taking a peak position as an initial value, setting parameters and boundaries such as area, center, width, trailing and the like, constructing a residual error minimization target, and performing robust fitting by adopting a trust region reflection algorithm; and indexes such as suitability, output peak area, center, broadening, separation degree, theoretical plate number and the like are verified by residual errors. According to the method, valley point or prior component information is not needed, the method is insensitive to noise and baseline drift, serious overlapping and trailing / leading edge peaks of multiple components can be effectively processed, convergence is high, the method is insensitive to initial values, parameters can be expanded to different peak shapes, and the method is suitable for qualitative and quantitative analysis of automatic and high-flux chromatographic data.

The invention discloses a detection method for simultaneous determination of lidocaine and prilocaine content in a lidocaine emulsifiable paste by high performance liquid chromatography, which comprises the following specific steps: step 1, taking lidocaine and prilocaine reference substances, and preparing a reference substance solution to detect the separation degree and theoretical plate number between lidocaine and prilocaine; step 2, taking the riptacaine cream, diluting with a solvent, and preparing a test solution; and step 3, acquiring chromatograms of the test solution and the reference solution under proper chromatographic separation conditions by applying high performance liquid chromatography and adopting a reversed-phase liquid chromatographic column, and quantitatively determining the content of lidocaine and prilocaine by an external standard method. The method overcomes the defects of complicated operation, poor durability, long detection time and poor specificity in the prior art, and has the characteristics of simplicity and easiness in operation, short running time, high detection efficiency, strong durability, strong specificity, good precision and high accuracy.

A method for extracting artemisinin, relating to the field of artemisinin extraction technology, includes the steps of extraction, enhanced extraction, separation, concentration, and purification. The purification employs an innovative column chromatography method, specifically a column height-to-diameter ratio of 1.2:1; adding hexane and diethyl ether eluent at a volume ratio of 8:2, with the added packing material height being 1.20-1.25 times the column diameter; and obtaining artemisinin after column chromatography. Alternatively, the innovative recrystallization method involves dissolving a paste in a crystallization vessel containing 50°C hot methanol, then lowering the temperature to 9-11°C, while locally heating and maintaining the temperature at the bottom of the crystallization vessel during cooling. Solid crystallization occurs under a uniform temperature distribution within the vessel, followed by filtration. This process is repeated twice to obtain artemisinin. The beneficial effects include an increased theoretical plate number of the chromatography column, significantly improved separation efficiency, and a significantly higher purity of artemisinin; the uniform temperature distribution within the crystallization vessel effectively improves the purity of the crystals.

The invention provides a method for detecting the dissolution rate of domperidone tablets, and relates to the technical field of analytical chemistry. According to the method, high performance liquid chromatography is adopted for determination, mobile phases comprise a mobile phase A and a mobile phase B, the mobile phase A is methanol-ionic liquid, the mobile phase B is an acetonitrile-glacial acetic acid solution, a gradient elution procedure is adopted, effective separation of domperidone and a large number of other auxiliary materials and impurities is achieved, the number of main peak theoretical plates of domperidone is larger than 3000, and the detection wavelength is 250nm. The domperidone component is exclusively and precisely measured, the quality evaluation of the dissolution rate of the domperidone tablet is greatly improved, and the detection method has high specificity and high sensitivity, and meanwhile, meets the green and environment-friendly requirements.

Methods and devices are disclosed for a separation device including a sintered polymeric monolith having polymeric microparticulate solids with a pore size from about 0.5 to about 8 microns, a porosity between about 50 percent to about 80 percent and a chromatographic uniformity characterized by an HETP (height equivalent of a theoretical plate) less than about 100 microns.

Methods and devices are disclosed for a separation device including a sintered polymeric monolith having polymeric microparticulate solids with a pore size from about 0.5 to about 8 microns, a porosity between about 50 percent to about 80 percent and a chromatographic uniformity characterized by an HETP (height equivalent of a theoretical plate) less than about 100 microns.

The invention belongs to the technical field of medicine detection, and discloses a detection method of doogliptin related substances, which comprises the following steps: mixing a monopotassium phosphate solution and acetonitrile to prepare a blank solution; the method comprises the following steps: mixing impurities of dogliptin with dogliptin to obtain a test sample; then carrying out solution and quantitative dilution on the test sample by using the blank solution as a diluent to prepare a standard test sample solution; detecting the labeled test sample solution by adopting a high performance liquid chromatography, wherein a mobile phase comprises an A-phase monopotassium phosphate solution and a B-phase acetonitrile. According to the present invention, the high performance liquid chromatography is adopted, the potassium dihydrogen phosphate and the acetonitrile are adopted as the diluents, the potassium dihydrogen phosphate-acetonitrile is adopted as the mobile phase system, and each chromatographic condition is optimized, such that the obtained chromatogram has characteristics of good peak pattern, specifically, the peak pattern of the main peak and each impurity peak is narrow, sharp, good in symmetry, high in theoretical plate number, and the like; and the sample injection precision is high, and the repeatability is good.