257 results about "Standard addition" patented technology

The invention discloses a method for simultaneously determining harmful elements in iron ore. The method comprises the following steps of: processing a sample through microwave digestion; under optimized instrument working conditions, drawing a standard curve by a standard addition method to correct the matrix effect; and simultaneously determining the harmful elements including sodium, potassium, lead and zinc in the iron ore by use of an inductive coupling plasma mass spectrometer. Through the invention, the problems of complicated operation and processing steps, low sensitivity, low stability, poor reproducibility and the like in the former determining process are solved; and the method disclosed by the invention has the characteristics of fast determination, high sensitivity and accurate result, and is favorable for environmental protection and human health.

The invention discloses a UPLC-MS / MS simultaneous flux detection method for multiclass veterinary drug residue in raw fresh milk. The method includes the steps of: (1) extracting a veterinary drug compound in a to-be-detected sample to obtain an extracted solution; (2) concentrating the extracted solution, and then regulating the pH to 7.5-10.0 to obtain a column passing solution; (3) activating a solid phase extraction column; and (4) loading the column passing solution on the activated solid phase extraction column, leaching the solid phase extraction column with leacheate, then conducting elution with eluent, collecting the eluent, carrying out concentration, redissolving and filtration by a filter membrane, then performing qualitative and quantitative determination by UPLC-MS / MS. The method provided by the invention can simultaneously detect 38 veterinary drug residue in raw fresh milk, and has the characteristics of high sensitivity and low detection limit. The matrix standard curve correlation degree, the standard addition recovery rate of the method and the intra-day and inter-day precision are all accord with the China, European Union and international veterinary drug residue analysis method requirements. The method provided by the invention provides efficient and accurate detection means for raw fresh milk veterinary drug residue risk analysis and warning research.

A new method to determine by quantitative analysis the amount of dye present in dyed engine oils is provided. The method uses imaging techniques, such as spectrophotometry, and a combination of dilution and standard addition techniques to quantitatively determine the concentration of dye in the engine oil to ascertain whether dye concentrations in engine oil have decreased as compared with original specifications, and to quantify the amount of dye to be added to the dyed engine oil to bring dye concentrations to original concentrations.

The invention discloses an enzyme linked immunosorbent assay method (ELISA) for detecting the total amount of diamond green and blank diamond green in measurement water sample and aquatic products, characterized in that: the modified compound of amido blank diamond green is synthesized and linked with the protein to produce immunogen and envelope antigen, and the polyclonal antibody of rabbit-anti colorless diamond green is obtained by immuning animal and the concentration range of ELISA standard curve is 0.1-100ng / mL, IC50 is 0.9-2.6ng / mL and the recovery of standard addition is 76.2-95%, the correlation coefficient of ELISA and HPLC is 0.975, n=7; because the cross-reaction rates of the prepared antibody and diamond green are respectively 95.25%, the ELISA can be used for measuring the total amount of the diamond green and blank diamond green without any oxidation step.

The invention relates to an automatic analyzer for determining the content of ammonia nitrogen in water and sewage through a flow injection colorimetric process and an automatic analytic method thereof. The automatic analyzer for determining the content of ammonia nitrogen in water and sewage comprises an automatic injection device, a peristaltic pump, a detector, and an online processing assembly, wherein the online processing assembly comprises a sample injection valve, braided reactors, three-way valves, a four-way valve, online heating modules, an online distillation module, an online degasser, and capillary connecting tubes. According to the automatic analyzer of the invention, samples can be continuously and automatically tested, the test speed is fast, fifty samples can be tested each hour, the test sensitivity is high, and the test accuracy is good; and according to the method of the invention, the liner range is 0.02-4.0mg / L, the liner correlation coefficient r is equal to or more than 0.999, the detection limit is 2.49mug / L, the standard addition recovery rate of practical water samples is 90-110%, the precision is high, and the repeatability is good.

The invention relates to a method for using a plasma atomic emission spectrometer to measure impurities in high-purity gold, which comprises the following steps: weighing one unit of sample in a bunsen beaker, adding aqua regia to dissolve, replenishing hydrochloric acid deionized water to do constant volume to a scale after dissolving, respectively getting sample solution in more than two colorimetric tubes, solution in each tube is 15ml, adding gold standard solution which is mixed by elements according to a multiple relation in turn, doing constant volume by deionized water, starting the plasma atomic emission spectrometer, starting a circulating water pump, opening analytic control software, entering a 'standard addition method' control procedure, choosing a spectral line for measuring in a spectral line base, setting the concentration value of curved lines, scanning a whole band, sucking sample solution in each colorimetric tube in an instrument in turn according to the sequence that the concentration is from low to high, clicking a feeler switch to get an initial curve point of the point after sucking in each time, assuring curved lines, and leading the linear coefficient to be more than 0.99, outputting the concentration value result of each determined element, and calculating the result of the percentage content of each determined element according to the calculating formula.

The invention discloses a silylation GC / MS (gas chromatography-mass spectrometry) detection method for simultaneous determination of saccharide, 1, 2-propylene glycol and glycerin in tobacco. A sample adopts DMF (dimethyl formamide) and BSTFA (N,O-bis(trimethylsilyl)trifluoroacetamide) as the extraction solvent and the derivatization reagent and has a derivatization reaction for 30 min in an oven at the temperature of 70 DEG C, DB-5MS chromatographic column with the size of 60m*0.25mm*0.25 mu m is adopted, and the content of 1, 2-propylene glycol, glycerin, fructose, glucose and sucrose is analyzed and determined with the GC / MS. Results show that the method has good linearity, the detection limit is 0.04-2.85 mg / g, the limit of quantitation is 0.13-9.61 mg / g, the average recovery of standard addition is 90.3%-114.4%, and the relative standard deviation is smaller than 9.1%. The use quantity of the sample and the reagent is small, the pretreatment is simple, and the method has the characteristics of fastness, simplicity, convenience, high sensitivity, high specificity and the like and is suitable for simultaneous determination of polyol compound and saccharide in a tobacco sample.

A method consists in measuring ac impedance spectrum using gold, platinum or carbon working ultramicroelectrodes (1). The direct current DC potential pulse which overlaps with alternating current AC signal of an amplitude in the range from 0.005 to 0.015 V and frequency in the range from 10<-2 >to 10<6>, Hz is applied at the electrode. The value of said DC potential pulse for a process of copper electrorefining is in the range from -0.4 to -0.9 V in relation to a platinum reference electrode (2). Resistance values characteristic of a given electrolyte (E) are obtained from said AC impedance spectrum and compared with standard characteristic obtained by standard additions method. A measuring system consist of electrodes (1, 2, 3) placed inside a measuring cell (4) filled with flowing industrial electrolyte. The electrodes (1, 2, 3) are joined to a spectrum analyser (12) controlled by a programming apparatus (13)

The invention discloses a method for detecting volatile organic chlorides in resin by using headspace gas chromatography. The method specifically is a headspace gas chromatography (HS-GC) method for detecting residual epichlorohydrin (ECH) and a by-product, 1,3-dichloro-2-propanol (DCP), in a polyamide polyamine epichlorohydrin (PAE) solution. The method is based on a phase balance achieved by a closed headspace bottle before GC detection under the headspace conditions of 60 DEG C and 30 minutes. An experiment proves that a PAE matrix solution affects the phase balance of a to-be-detected substance. Therefore, the accuracy of the method is tested by adopting a standard addition method. The result shows that the method has relatively good precision (RSD is smaller than 2.90%) and accuracy (the recovery rate range is 93.6%-105%). Therefore, the method is suitable for analysis of volatile organic chlorides in a PAE resin solution.

The invention relates to a fast extraction, purification and detection method for Sudan red dye residues in food. The food is one of eggs, chilies and chili oil. The method comprises the following steps: an egg sample or a chili sample is extracted with acetonitrile-dichloromethane mixed liquor and then purified with a strong cation solid-phase extraction column, while a chili oil sample is mixed with dichloromethane-n-hexane and directly purified with the column; and detection is performed with UFLC-MS / MS (ultrafast liquid chromatography tandem mass spectrometry). The method overcomes the defect of low recovery rate of Sudan red III and Sudan red IV, solves the problems that the egg sample is dispersed easily and effective solid-liquid separation cannot be realized easily, and has the advantages of simple steps and convenience in operation; meanwhile, purified liquor after treatment is subjected to Sudan red content detection with the UFLC-MS / MS, the defects of poor sensitivity, low accuracy, high false positive rate and the like of the conventional liquid chromatography are overcome, the recovery of standard addition of four Sudan red dyes is 90.6%-99.4%, and the detection limit is 0.1-0.5 mu g / kg.

The invention relates to a method for rapidly and simultaneously determining the content of major element titanium and minor elements, namely, silicon, aluminum, manganese, nickel, vitriol, molybdenum, chromium, phosphorus and copper in 70 ferrotitanium through microwave digestion-ICP-AES. The method comprises the steps that a sample dissolving method, the microwave digestion conditions and the matrix interference condition are investigated and researched, an IEC data model is incorporated into method establishment, interference of the major element Ti to the trace element P can be sheltered, and the interference degree is decreased to minimum; detection limits of all the elements are determined finally, and a precision experiment and a standard addition recovery experiment are conducted. It is shown through the result that for the method, the relative standard deviation (n=8) ranges from 1.24% to 6.72%, and the standard addition recovery rate ranges from 92.6% to 105.1%. The method is advanced and reliable, the analysis cycle is short, ten elements can be determined rapidly and simultaneously through one-time sample decomposition, synchronous analysis of the major element and the minor elements is achieved successfully, and the method is suitable for analysis of 70 ferrotitanium.

The invention discloses an analysis method for amide compounds. The analysis method adopts a gas chromatography-mass spectrometry method. According to the invention, under the optimized analysis conditions, very good chromatographic peaks of the five amide compounds can be obtained within 15 min; very good separating effects can be obtained; the linearities of all the target compounds are good within a concentration range of 0.01-10 mg / L; the correlation coefficients are all greater than 0.9995; the detection limits reach 0.01 mg / kg; the relative standard deviations are smaller than 2.5%; the recovery rates of standard addition are 80-105%. The analysis method is convenient, fast, accurate, and reliable, and can meet REACH regulation requirements on hazardous amides.

The invention discloses a method for carrying out illegal cooking oil detection by using an ultraviolet spectroscopic analysis method. The method comprises the steps that: (1) an oil sample to be detected is subjected to pretreatment; (2) a standard curve is drawn by using a substrate standard addition method; a mixed oil product and a standard normal oil product are respectively pretreated by using the method provided by the step (1), and are scanned by using an ultraviolet spectrum colorimetric analysis method at wavelengths of 200-320nm; aqueous solution spectral absorption diagrams of the two samples are drawn and are adopted as standard curves of the two which are detection limits of illegal cooking oil detection; (3) a micro-emulsion liquid of oil in water molecules (W / O) is scanned by using an ultraviolet spectrum colorimetric analysis method at wavelengths of 200-320nm; an aqueous solution spectral absorption diagram of an oil sample to be detected is drawn; and whether the detected oil sample is illegal cooking oil is determined according to absorption value volume, spectral characteristics curve, and curve graphic similarity of the aqueous solution spectral absorption diagrams. Through many tests and validations, the success rate of the method can substantially reach 70-80%.

The invention discloses an ELISA analysis method for content of sudan red No.1 in food. It is characterized in that two sudan red derivatives with different carbon bridge lengths are compounded and derivatives are crosslinked with carrier protein to obtain four polyclonal antibodies. There are eight test combinations. Seven combinations can be used for immunoassay to sudan red No.1. Concentration range of standard curve is 0.1-100ng / mL and IC50 is 0.3-2.0ng / mL. Cross reaction rate of four antibodies and sudan red No.2-4 is 0.1-14.3%. There is almost no cross reaction between four antibodies and six pigments added in food. It shows that antibodies have very high specificity to sudan red No.1. Six commercial foods can be used as samples. After it is treated simply, extract liquid is diluted directly for ELISA measurement. The recovery of standard addition for sudan red No.1 is 92.4-114% and relative standard deviation is 5.9-24.8%. Samples with standard addition are analyzed by HPLC and are contrasted with ELISA results. Two methods have higher relativity (R=0.9851; n=7).

The invention belongs to the field of product quality detection and in particular relates to a rapid detection method of residual amount of dimethylformamide in textiles. The method provided by the invention comprises the following steps of: preparing a guide sample and an internal standard solution; pre-treating the sample; extracting DMF (Dimethyl Formamide) in the sample; carrying out GC / MS (Gas Chromatograph / Metabolic Syndrome) analysis; and detecting the content of DMF through a standard addition method. The method provided by invention can be used for detecting the residual amount of DMF in products including leather, textiles, paper products and the like and various raw materials. Compared with the prior art, the method disclosed by the invention has the advantages of flexibility, accuracy, environment friendliness, simplicity, reliability and easiness of being popularized and is highly effective in detection of the residual amount of DMF in various products and raw materials.

The invention provides a fast detection method of benzo(a) pyrene in high-fat foods, relating to a detection method of benzo(a) pyrene, which has simple and fast operation and low cost. The method comprises the following steps of: placing a sample of high-fat foods in a ground suction bottle, adding a potassium hydroxide-methyl alcohol solution and normal hexane, extracting together with water in a microwave oven, taking out, cooling, flushing, taking out a clear liquid of normal hexane after settlement and stratification, drying by rotary evaporation, and determining the volume by using dichloromethane to obtain a sample solution to be detected; mapping the constant energy synchronous fluorescence spectra of the sample solution to be detected by using a fluorescence spectrophotometer with derivative-constant energy synchronous scanning for the identification and the rough detection of benzo(a) pyrene; and adding a second derivation function, mapping second derivate-constant energy synchronous fluorescence spectra, reading data by adopting a derivate baseline method, and determining the quantity of benzo(a) pyrene in the sample solution to be detected by using a continuous standard addition method.

A new method to determine by quantitative analysis the amount of dye present in dyed engine oils is provided. The method uses imaging techniques, such as spectrophotometry, and a combination of dilution and standard addition techniques to quantitatively determine the concentration of dye in the engine oil to ascertain whether dye concentrations in engine oil have decreased as compared with original specifications, and to quantify the amount of dye to be added to the dyed engine oil to bring dye concentrations to original concentrations.

The method consists in registering curves by cyclic voltammetry method in the range of copper ion concentration up to 20 g / l or alternately by chronoamperometric method in the range of concentration from 20 to 60 g / l. A platinum or gold microprobe of a diameter in the range from 1 to 50 um and a copper plate reference electrode are used. The value of current density read off from said curves is compared to the calibration curves previously determined by standard additions method. For high concentration in the range from 20 to 60 g / l the calibration curves obtained in the range of temperatures from 15 to 60° C. are registered.

The invention relates to a method for measuring phosphorus content in chromite. According to the method, a chromite sample is decomposed by high-temperature alkali fusion of sodium peroxide, the melt is extracted by hot water, phosphorus co-precipitates with elements such as iron, magnesium, manganese and the like, chromium enters the solution in a form of CrO4<2->, sodium hydroxide solution is used for washing so as to remove the chromium. The precipitate is subjected to acidolysis by hydrochloric acid and the precipitate subjected to acidolysis is then transferred into a volumetric flask. The test solution is separated, the pH value of the solution is adjusted by taking paranitrophenol as an indicator, phosphorus-molybdenum heteropoly acid is reduced to be phosphomolybdenum blue by taking ascorbic acid as a reducing agent in hydrochloric acid medium, and the light absorption value of the test solution is measured at the position of 680nm of a spectrophotometer. According to the technical scheme of the method, the design is reasonable, the relative standard deviation is less than 12%, and the recovery rate of standard addition reaches up to 96-99%; compared with the standard sample reference value, the method has the advantages that the analysis data is basically identical, the results are stable and accurate, simplicity and convenience are realized, and the operability is high.

The invention discloses a fluorescent detection method of benzo (a) pyrene in edible oil, relates to a detection method of edible oil, and provides a fluorescent detection method of benzo (a) pyrene in edible oil, wherein the method is is simple, convenient and quick to operate, and the cost is low. The fluorescent detection method comprises the following steps: adding a dimethyl sulfoxide solvent in the edible oil; extracting and taking out the extracted product; s layering by standing or centrifuging; re-extracting the separated oil layer on the upper layer once, and collecting the dimethyl sulfoxide extraction liquid twice as liquid to be detected; plotting the liquid to be detected by a fluorescence spectrophotometer with derivative-constant energy isochronous scanning according to the following constant energy synchronizing fluorescence spectra conditions, and reading the fluorescence intensity of the benzo (a) pyrene by constant energy difference to identify the benzo (a) pyrene and measure roughly; and adding a second-order derivation function under the plotting conditions of the constant energy synchronizing fluorescence spectra to plot the derivative-constant energy synchronizing fluorescence spectra; reading the fluorescence intensity of the benzo (a) pyrene; and measuring the benzo (a) pyrene quantitatively by utilizing a continuous standard addition method.

The invention discloses a method for testing tin content of a tin-lead solder through a flame atomic absorption spectroscopy method. According to the method, nitric acid, hydrofluoric acid and hydrogen peroxide are used as solvents to rapidly decompose the tin-lead solder, the ratio of the nitric acid to the hydrofluoric acid to the hydrogen peroxide is 1:2:1, a sample is heated and dissolved by an electric heating plate at the low temperature, the absorbancy of the tin in a decomposition solution is measured by using the air-acetylene fuel-lean flame atomic absorption spectroscopy method, and the tin content in the decomposition solution is calculated by using a standard addition method. The method is high in testing accuracy and relatively small in error, the whole analysis test process is simple in operation, the amount of acid used is small, and the method is capable of rapidly analyzing the tin content of the tin-lead solder.

The invention discloses a determination method of the content of endogenous hormones in terminal buds of tomato plants. The method comprises the following steps: 1) preprocessing a tomato terminal bud sample for test; 2) preparing a mobile phase and setting chromatographic conditions; 3) preparing a standard liquid; 4) inspecting specificity; 5) inspecting a linear relation; and 6) determining sample content. The method of the step 1) comprises process of performing vacuum evaporation after extraction and petroleum ether extraction, further regulating pH, carrying out ethyl acetate extraction, and finally performing secondary vacuum evaporation to obtain a to-be-determined sample liquid; and in the step 2), the mobile phase is prepared from methanol and 0.075% glacial acetic acid. The determination method of the content of endogenous hormones in terminal buds of tomatoes by HPLC, provided by the invention, can quickly, accurately and simultaneously determine the content of four plant endogenous hormones, and has the characteristics of fast and efficient determination, high sensitivity and high degree of automation; a recovery of standard addition experiment is carried out, the average recovery is 99.85%, and RSD (Relative Standard Deviation) is less than 1.56%, which meets the hormone determination requirement.

The invention provides a method for detecting abscisic acid and jasmonic acid in fresh tobacco leaves through liquid chromatogram-tandem mass spectrometry. The method comprises the following steps: (1), preparing an extraction solvent; (2), carrying out liquid nitrogen quick freezing on fresh tobacco leaves, and freezing, drying and smashing; (3), adding the extraction solvent into the well smashed samples, and carrying out low temperature extracting; (4), carrying out refrigerated centrifugation, taking supernate and filtering; (5), carrying out LC-MS / MS detection. The method provided by the invention has the following advantages: a pretreatment method is simple, only ultrasound and filtering are required, and solid phase extraction column purification treatment is not required. Compared with the conventional method, the method provided by the invention adopts LC-MS / MS, the sensibility is high, the accuracy is high, the recovery of standard addition is high, and pretreatment for 100 samples consumes less than 2 hours while methods in existing documents require tedious and time-consuming pretreatments, and about three days are required for 100 samples. Therefore, the method provided by the invention can effectively improve analysis efficiency, and is suitable for analyzing low content objects in a complex matrix.

A spinning cell device is described for fast and convenient standardization and analysis of constituents and isotopes in solid samples by laser ablation inductively coupled plasma (LA-ICP) spectrometry. The method and apparatus for performing he method require the sample under test and a standard to be spun during ablation allowing the quasi-simultaneous ablation of both materials. The aerosols resulting from the ablation of sample and standard are mixed in the ablation cell allowing quantification of the ablated metals by the method of standard addition or isotope dilution. The relative proportion of standard verses sample ablated can be changed by altering the trajectory of the laser beam. The ablated aerosol is swept into an inductively coupled plasma by a carrier gas and analyzed by mass spectrometry.

The invention discloses a sample pretreatment method for determining the content of chloride ions and sulfate radicals in limestone solid, which comprises grinding a limestone sample, sieving with a 110 mesh sieve, and sealing in a sample flask; accurately weighing the limestone sample, adding a certain concentration of an acid solution for dissolving the sample to ensure the chloride ions and sulfate radicals to be fully released into the solution, and diluting to a constant volume; and neutralizing the sample solution with a certain concentration of alkali to regulate a pH value to a certain range, performing membrane filtration, and determining the content of chloride ions and sulfate radicals in the sample by ion chromatography. The method has simple process, easy operation, good repeatability, relative standard deviation smaller than 1.68%, and recovery of standard addition above 94.1%.

A method of determining the concentration of iron in a sample, characterized by bringing the iron contained in the sample into contact with an iron-chelating color former in the presence of lithium ions and determining the iron concentration based on the degree of the resultant coloring; and a reagent and kit for iron determination which are for use in the method. This method eliminates the conventional problem that found values obtained are low as compared with ones obtained by the international standard method. This method does not necessitate a complicated operation, e.g., protein removal, and enables the determination of an iron concentration with an autoanalyzer. Since found values obtained by the method are close to ones obtained by the standard addition method according to the international standard method, more accurate determination is possible.

The invention relates to a method for determining the content of eugenol in formulated cut tobacco. The method comprises the steps of: preparation of an extraction reagent and a sample solution, liquid chromatogram analysis and detection result calculation, etc. The optimized detection method has the advantages of short detection time, simple operation, high sensitivity, and good repeatability, etc. The chromatographic condition of the method in the invention makes the chromatographic peak of eugenol and the chromatographic peak of impurities well separated. And the method of the invention also has good linear range, the detection limit is 0.3 microgram / g, the average recovery rate of standard addition is 101.4%, and the average relative standard deviation is less than 2.4%.

The invention belongs to the technical field of radioactive substance processing methods, and particularly relates to a method for analyzing fluorine ion concentration under a radioactive condition. The method is characterized in that a fluorine ion selective electrode method is adopted, by using sulfosalicylic acid-trisodium citrate as a total ion strength regulation buffer solution, the calculation is carried out by using a secondary standard addition method under a condition that pH is 8-9 so as to obtain F-concentration in an original sample. Aiming at the sample containing BF<4><->, the method provided by the invention has the advantages that complexing action on the ion F by the ion Al is skillfully utilized to ensure that BF<4><-> is completely hydrolyzed; in an analyzing process, distillation operation is avoided, and the loss of radioactive substances is reduced; moreover, a value of a slope S is not needed, and therefore, the errors caused by improper setting of the slope S can be avoided.