52 results about "N-nitrosamine" patented technology

An automated headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry for the determination of four N-nitrosoamines in groundwater samples is developed. Response surface methodology technique was employed to investigate the optimized extraction conditions of headspace solid-phase microextraction using CombiPAL autosampler. The method was applied to determine the N-nitrosamine concentrations in groundwater samples.

The invention belongs to the field of environment detection and analysis and in particular relates to a method for detecting trace N-nitrosamine in water. The method comprises the following steps: a)mixing a water sample to be tested with N-nitroso-dimethylamine-d6, feeding through an activated carbon solid-phase extraction column, extruding off moisture in the activated carbon solid-phase extraction column, further eluting the activated carbon solid-phase extraction column with dichloromethane, and collecting an eluent; b) mixing the eluent with methanol, concentrating so as to obtain a concentrated liquid, mixing the concentrated liquid with N-nitroso-dimethylamine-d14 so as to obtain a sample to be analyzed; c) performing gas chromatography-mass chromatography detection on the sample to be analyzed, and calculating the type and the content of N-nitrosamine in a water sample to be detected according to detection results and standard curves established in advance. The method providedby the invention is simple and convenient in water sample pretreatment step, easy to operate, relatively low in price of GC-MS (Gas Chromatography-Mass Chromatography) equipment used in sample analysis, and relatively good in popularization prospect.

The invention belongs to the technical field of chemical tests on cigarette smoke and particularly discloses a method for determining tobacco-specific N-nitrosamine and polycyclic aromatic hydrocarbons in mainstream smoke of cigarettes simultaneously. According to the method, a smoking machine smokes cigarettes, a Cambridge filter traps the mainstream smoke of the cigarettes, the filter is filtered by solutions containing interior labels, and an extraction solution is directly detected by an on-line gel chromatography-gas chromatography-tandem mass spectrometer after being filtered. Compared with a standard method, the method has the advantages that two compounds are determined together and the test efficiency is improved; all that is need for detection is to filter the smoke extraction solution, so that the method is convenient to operate, quick and efficient; the on-line gel chromatography-gas chromatography-tandem mass spectrometer is used for detection, and thus the automation degree is high and organic solvent consumption is low.

The invention provides a method for measuring tobacco-specific N-nitrosamine in tobacco. The method adopts gas chromatography triple quadrupole mass spectrometry (GC-QQQ-MS/MS) to measure the content of tobacco-specific N-nitrosamine in tobacco and specifically comprises the following steps: 1, preparation of a standard solution; 2, sample pretreatment; 3, qualitative detection of samples; 4, quantitative detection of samples. According to the method for measuring tobacco-specific N-nitrosamine in tobacco, an optimally-selected mixed solvent is used for extraction, so that the sample pretreatment method is optimized; besides, simple and fast measurement is performed on the basis of high chromatographic fractionation capability and good selectivity and sensitivity of the GC-QQQ-MS/MS, so that higher sensitivity, accuracy and precision can be achieved, and the detection efficiency of four kinds of tobacco-specific N-nitrosamine in tobacco can be improved effectively.

The invention discloses a determination method of volatile N-nitrosamine in tobacco, tobacco products and smoke and belongs to the technical field of tobacco chemical inspection. The determination method comprises the steps that graphitized carbon black, N-propyl ethylenediamine bonded silica gel, anhydrous magnesium sulfate and a sodium chloride adsorbing agent are added into a sample extracting solution, centrifugation and filtration are carried out after dispersive solid-phase extraction, and a to-be-tested solution is obtained; the to-be-tested solution is taken for gas chromatography-tandem mass spectrum analysis, the content of volatile N-nitrosamine in the to-be-tested solution is obtained with reference to a standard curve, and the content of volatile N-nitrosamine in a sample is obtained through calculation. The method is high in detection sensitivity, good in accuracy and repeatability and easy, fast and efficient to operate, the relative recovery rate is between 82.4% and 112.4%, and the intra-day precision and inter-day precision are smaller than 9.1% and 8.2% respectively.

The invention belongs to the field of environmental protection, and particularly relates to a preparing method of a compound adsorbing material, which comprises the following steps: drying remaining active sludge, and then obtaining the dried sludge; conducting thermal cracking of the dried sludge in the environment of protective gas and then obtaining the compound adsorbing material, wherein the temperature for thermal cracking is 500-800 DEG C. Under the process of thermal cracking in high temperature, pathogens and persistent organism in the sludge are charred, heavy metals are solidified, consequently requirement of 'hazard free' can be met. The compound adsorbing material has a good adsorbing effect on harmful gases such as sulfuretted hydrogen, sulfur dioxide, nitric oxide, drugs in waste water(especially antibiotics), volatile cancerigenic organic compounds, N-nitrosamine, and phosphate. The compound adsorbing material can be used for disposing sewage or harmful gases, improving environment, and turning waste into wealth, not only broadening the scope of materials for preparing the compound adsorbing material but also realizing the integration of sludge harmfulness and resource utilization.

The present invention discloses the composition of antioxidant of bamboo leaves (AOB) and its use. The purpose of present invention is to provide a new food additive which is natural, nutritional, and muti-functional, and which is of rich resources, safety, good effect, and low cost. AOB is yellow or brown powders or particles obtained from bamboo leaves, wherein the main antioxidative components include flavones, lactones, phenolic acids. AOB can either inhibit lipid autoxidation chain reaction, or chelate transitional metal ions, and can be used as primary and second antioxidant. AOB can eliminate nitrite and inhibit the synthesis of N-nitrosamine, and has anti-bacteria, bacteriostatic, deodorizing, aroma enhancing etc. functions. AOB can be commonly used in oil-containing food, meat product, fishery product, expanded food etc. food systems.

The invention belongs to the technical field of chemical examination of cigarette smoke and particularly discloses a method for simultaneously testing specific N-nitrosamine and polycyclic aromatic hydrocarbon of tobacco in main stream smoke of a cigarette on the basis of tip-microextraction. According to the method, a smoking machine is used for smoking the cigarette, a Cambridge filter is used for capturing the main stream smoke of the cigarette, a solution containing internal labels is used for extracting the filter, and an extracting solution is detected after being subjected to tip-micro solid-phase extraction purification. Compared with a standard method, the method is used for testing two compounds simultaneously, and the testing efficiency is improved; detection can be performed after tip-micro solid-phase extraction purification of the extracting solution of the smoke, and the method has the advantages of simplicity and convenience in operation, fastness and efficiency.

The invention relates to a method for preparing pendimethalin by aminating dimethyl-dinitro anisole. The method comprises the following concrete steps of: firstly, mixing, heating and refluxing 3,4-dimethyl-2,6-dinitroanisole, catalyst and excessive 3-pentyl amine for carrying out aminating reaction to generate N-(1-ethyl propyl)-3,4-dimethyl-2,6-dinitraniline; and secondly, distilling and reclaiming the unreacted 3-pentyl amine, cooling residues, and dissolving the cooled residuces with absolute ethanol, filtering to remove the catalyst and other insoluble substances, then removing ethanol to obtain 98 percent pendimethalin raw drug with the yield over 92 percent. Compared with the traditional synthetic production process of the pendimethalin raw drug, the preparation method not only has high yield, favorable quality and less wastewater, but also more importantly puts an end to the generation of N-nitrosamine substances in the pendimethalin raw drug.

The invention discloses a method for purifying pendimethalin, which comprises the following steps of: adding coarse product of pendimethalin, thiocyanate and hydrochloric acid into a reaction container according to a mass ratio of 7-10:1:3-5; performing reflux reaction at the temperature of between 75 and 81 DEG C for 6 to 15 hours under normal pressure, adding the thiocyanate again in the reaction process for continuous reaction until the content of N-nitrosamine compound is less than 10ppm, and taking an oil layer after the reaction is finished; and washing the oil layer with water, alkali and water in turn and controlling the temperature to between 60 and 90 DEG C under the vacuum condition for removing a solvent so as to obtain the pendimethalin. The method for purifying the pendimethalin has the advantages that: due to the existence of the aid thiocyanate, the speed of the reaction for removing the N-nitrosamine compound is high, and the content of the N-nitrosamine compound is less than 20ppm; because the reaction temperature is controlled at the reflux temperature, the method does not need to be operated under the pressure condition, and can reduce the operating difficulty and equipment requirement and improve the operating safety.

The invention discloses a tobacco leaf pretreatment method during tobacco primary processing. The tobacco leaf pretreatment method comprises the following steps of: performing dispersion and moisture regaining on a tobacco, conveying to digesting equipment for digesting through conveying equipment, wherein temperature of hot water of the digesting equipment is set between 70 and 100 DEG C; digesting the tobacco for 5 to 15 minutes; conveying the tobacco to a draining device for draining; spraying to add a lining; dehumidifying by hot air; and after reducing the water to 22 percent, laying the leaves for 15 to 30 minutes and cutting. In the tobacco leaf pretreatment method, the tobacco is dispersed and subjected to moisture regaining, so that the storage time of the tobacco added with the lining can be reduced, the working efficiency is improved and the time is totally reduced by 100 minutes due to a tobacco digesting mode; furthermore, the cigarette sense smoking quality is improved, the chemical constituents of a cigarette are coordinated, and harmful substances, such as oil tar of smoke, smoke nicotine, CO and N nitrosamine in the cigarette (TSNAs), can be reduced greatly; therefore, the quality of cigarettes is improved.

The invention provides a preparation method of a Western style smoked and cooked sausage with low contents of nitrite and N-nitrosamine. The preparation method comprises the following steps: materialselection and preparation, pickling, sausage filling, cooking, smoking and the like. By controlling and optimizing process conditions of cooking time, a cooking temperature, smoking time, a smoking temperature and the like, three additives including a rosemary extract, a grape extract and tea polyphenol are added, and optimal addition amounts are selected, so that the residue amount of the nitriteand the content of nitrosamine in the Western style smoked and cooked sausage are remarkably decreased, the problems that the residue amount of the nitrite is high and the content of the nitrosamineis difficult to control in a preparation process of the Western style smoked and cooked sausage are solved, deficiencies in the prior art are remedied, carcinogenic risks of the Western style smoked and cooked sausage are reduced, and theoretical foundations and technical supports are provided for development of meat products with low contents of the nitrite and the nitrosamine as well as researches about formation and inhibition mechanisms of the N-nitrosamine in future.

The invention discloses a method for detecting N-nitrosodimethylamine in meat products, which comprises the steps of S1, taking a sample to be detected, adding n-hexane, acetonitrile and water, oscillating, centrifuging and discarding the n-hexane layer; S2, adding dichloromethane and anhydrous sodium sulfate to the solution in the step S1, oscillating and centrifuging, taking an organic layer into a concentration bottle, adding ice water to a receiving bottle, carrying out rotary evaporation under the conditions of 350-360 mbar and 34-36 DEG C to remove dichloromethane, and if the remaining solution is greater than 1mL, adding dichloromethane for continuous rotary evaporation until the remaining solution is about 0.5-1mL; S3, removing the residue in the step S2, cleaning the concentrationbottle in the step S2 with a small amount of acetonitrile, n-hexane saturated with acetonitrile and n-hexane in sequence, mixing the washing liquid and the residue in the step S2, centrifuging, discarding the n-hexane layer, enabling the acetonitrile layer to be constant in volume to obtain the sample solution to be detected, and carrying out GC-MS determination. The pretreatment method applied by the invention is easy to operate, the high grease in the sample to be detected can be effectively removed, and the recovery rate of NDMA is significantly improved through improving the concentrationcondition at the same time.

The invention relates to an extraction and determination method of special N-nitrosamine of tobacco in tobacco or a tobacco product based on hydrophobic ionic exchange solid phase extraction and belongs to the technical field of tobacco chemical examination. The extraction method, provided by the invention comprises the following steps of: adding the tobacco or the tobacco product into an ammonium acetate solution, the concentration of which is 5-100mmol/L, to be extracted; passing the obtained coarse extraction liquid through an activated HiCapt MCX solid extraction column; and then leaching and eluting the liquid to obtain the N-nitrosamine. The extraction method of special N-nitrosamine of tobacco in tobacco or the tobacco product based on hydrophobic ionic exchange solid phase extraction provided by the invention can effectively remove impurities and interferents, shorten the treatment time and improve the accuracy and precision of the determination method. The relative recovery rate of the method is between 92.2% and 108.9%. The within-day precision and the between-day precision are separately smaller than 4.6% and 4.2%.

The invention discloses a tobacco additive and application thereof. The tobacco additive comprises, by weight, 20-40 parts of squalene, 0.2-0.8 part of organic acid, 0.5-1.5 parts of a tobacco fragrance-enhancing agent and 50-90 parts of an organic solvent. According to the tobacco additive, the organic acid and the tobacco fragrance-enhancing agent are added to the squalene and dissolved in the organic solvent to obtain the tobacco additive, the functions of the squalene of selectively clearing away harmful substances of nitrogen oxides, polynuclear aromatic compounds, N-nitrosamine, free radicals and the like in cigarettes is retained, the functions of inhibiting the canceration, mutation and the like caused by smoke can be retained, the harmful substances in the cigarettes can be selectively reduced by applying the tobacco additive to the cigarettes and spraying on the surfaces of cut tobaccos, so that the harm of the cigarettes is reduced, the safety of the cigarettes is improved,the aroma of the cigarettes can be improved, the coordination and aftertaste of the cigarettes are improved, offensive flavors and irritation are reduced, and therefore the oral cavity comfort of thecigarettes is integrally improved.

The invention discloses a thermal-insulation water tank for a water heater. The thermal-insulation water tank for the water heater structurally comprises a casing, a thermal insulation layer and an inner container sequentially from outside to inside, wherein a heat exchanger is arranged in the inner container and comprises a stainless steel corrugated pipe, one end of the stainless steel corrugated pipe is connected with a water inlet, and the other end of the stainless steel corrugated pipe is connected with a water outlet; an exhaust hole and a liquid supplement port are formed in the upper part of the casing and communicated with an inner cavity of the inner container; a liquid discharge hole is formed in the lower part of the casing and communicated with the inner cavity of the inner container; a standby water inlet and a standby water outlet are formed in the casing and both communicated with the inner cavity of the inner container. The inner container can be made of a non-food-grade material, the production cost is reduced, and the yield of a product is increased. The quality of flow-out water is better, energy is saved, the production cost of the water tank is substantially reduced, the water tank is economical and practical, flow-out water is fresh, nitrosamine cannot be generated, and the water tank is safer to use and wider in application.

The invention relates to a method for quickly detecting volatile N-nitrosamine in cosmetics. The method comprises the following steps: weighing a small amount of cosmetics; adding ammonium sulfamate and acetone, performing ultrasonic dissolution and refrigerated centrifugation, and extracting with a dichloromethane layer; and performing a gas phase chromatography-thermal energy analyzer method on the extract solution to realize quantitative detection of a target compound. According to the invention, the method can effectively detect out volatile N-nitrosamine in water-soluble or fat-soluble cosmetics, has the advantages of simple pretreatment, little time consumption, low cost and high accuracy, is applicable to actual detection of cosmetics, and can provide a technical method support for detection of volatile N-nitrosamine in cosmetics and production quality control.

The invention relates to a bitter melon extract and application of the extract in reduction of an N-nitrosamine compound in cigarette smoke. Specifically, a preparation method of the bitter melon extract comprises the following steps that 1, bitter melons are subjected to ultrasonic extraction in an alcohols solvent, and filtration and filtrate collection are performed; 2, the filtrate collected in the step 1 is concentrated and extracted, an organic phase is collected, dried and concentrated to obtain the bitter melon extract. The content of the nitrosamine compound in a main smoke flow can be reduced, the bitter melon extract can coordinate with the cigarette smoke to improve the sweet aftertaste of the smoke.

The invention belongs to the technical field of food processing, and provides a spice essential oil composite inhibitor for blocking NDMA generation in an in-vitro simulated nitrosation system in order to solve the problem that a spice with a good effect of blocking N-nitrosamine generation is lacked at present. The spice essential oil composite inhibitor is prepared by mixing essential oil of five spices including pepper, ginger juice, Chinese prickly ash, anise and clove. In the in-vitro simulated nitrosation reaction system, the NDMA inhibition effect of nine kinds of commercially availablespice essential oil is researched through a single-factor test, and the optimal ratio is screened by virtue of a secondary regression orthogonal combination test design. Data support is provided forlater development of safe and delicious meat product spice combinations. The prepared spice essential oil composite inhibitor can be used for inhibiting formation of N-nitrosamine in meat products, also endows the meat products with special flavor, and has important guiding effect on safe and delicious meat product development.

The invention discloses a method for determining special tobacco N-nitrosamine in the cigarette liquid of an electronic cigarette. The method is characterized by comprising the following steps: diluting a cigarette liquid sample of the electronic cigarette by using a phosphate buffer solution containing ascorbic acid, and then performing extraction by using dichloromethane; concentrating an extracting solution, then performing determining by using online gel permeation chromatography-gas chromatography-tandem mass spectrometer, and performing quantification by using an internal standard method. The method for determining the special tobacco N-nitrosamine in the cigarette liquid of the electronic cigarette is brand new, and has the advantages of high sensitivity, good matrix removing effect and strong anti-jamming capability.

The invention discloses a method for analyzing N-nitrosamine compounds in drinking water. The method comprises the steps that a) sample pretreatment: a water sample of 100 mL is taken and filtered with a 0.45-micron nylon membrane to acquire a pretreated sample; b) solid phase extraction cartridge pretreatment: a solid phase extraction cartridge is rinsed with 10 mL of dichloromethane for the first time, 10 mL of methanol for the second time and 10 mL of distilled water for the third time to acquire a pretreated solid phase extraction cartridge; c) loading: the pre-treated sample is poured into the pretreated solid phase extraction cartridge, and a negative pressure suction method is used to enable the pretreated sample to pass through the pretreated solid phase extraction cartridge untilthe pretreated sample in the pretreated solid phase extraction cartridge is drained to acquire the solid phase extraction cartridge to which a target analyte is adsorbed; d) the analyte is collected;and e) analysis is carried out. According to the invention, the method has the advantages of easy processing and high sensitivity; the linearity is great from 0.5 to 100 mu g/L; a standard solution of0.5 mu g/L is injected continuously for 5 needles; the peak area RSD is less than 2%; and the reproducibility is great.