An impurity A, an impurity B and an impurity G and preparation methods therefor, and an application as a reference standard for quality control of a compound as represented by formula VI are described.

##STR00001##

Provided is a method for detecting impurities in ammonium hydroxide. The method for detecting impurities in ammonium hydroxide includes preparing a potassium permanganate solution, preparing ammonium hydroxide, and adding the potassium permanganate solution several times to the ammonium hydroxide so as to detect impurities in the ammonium hydroxide. Potassium permanganate contained in the potassium permanganate solution is added for each time in the range of 0.0001 mol to 0.01 mol per 1 g of ammonia contained in the ammonium hydroxide.

An improved analytical method for analysis of dianhydrogalactitol preparations provides a method for determining the purity of dianhydrogalactitol and detecting impurities in preparations of dianhydrogalactitol, as well as identifying any such impurities. The method employs high performance liquid chromatography (HPLC), in particular, HPLC with evaporative light scattering detection (ELSD); the HPLC can be followed by tandem mass spectroscopy. The method can further comprise the step of performing preparative HPLC collection of at least one specific substance peak present in a preparation of dianhydrogalactitol.

Provided is a fluorine-containing solvent for gas chromatography mass spectrometry of fluorine-containing substances found contaminating surfaces of fluororesin melt-molded products and detrimental to the use of such products for handling fluids in semiconductor manufacture. Also provided is a quantitative determination method for such fluorine-containing substances and a qualitative analysis method for such fluorine-containing substances based on a gas chromatography mass spectrometry method using the fluorine-containing solvent to enable the determination of the presence or absence of trace amounts of contaminant fluorine-containing substances existing as fine particles on surfaces of melt-molded fluororesin products.

The present invention relates to an early warning method before the occurrence of aflatoxin contamination. The steps are as follows: extracting toxins from the sample to obtain a sample extract, and subjecting the sample extract to detection and analysis by liquid chromatography-high resolution mass spectrometer, performing qualitative analysis based on the mass spectrometry information to obtain qualitative results, performing quantitative analysis based on a standard curve of the chromatographic peak area of each warning molecule/the peak area of the internal standard-warning molecule concentration to obtain quantitative results of these warning molecules, wherein a risk of aflatoxin contamination of the sample is assessed to obtain a classification prediction model, inputting the quantitative results of the warning molecules for a toxigenic strain of Aspergillus flavus, and outputting a risk assessment result based on the classification prediction model, thereby achieving the early warning before aflatoxin contamination occurs.

The present invention relates to an aflatoxin contamination risk warning molecule and use thereof. The steps are as follows: weighing a quantitative sample, extracting the aflatoxin contamination risk warning molecule to obtain a sample extract, and detecting and analyzing the sample extract to obtain a quantitative result of the aflatoxin contamination risk warning molecule; performing modeling with a chemometrics method using the content of one or more of the aflatoxin contamination risk warning molecules as a variable to obtain a classification prediction model, and performing risk assessment on aflatoxin contamination risk of the sample based on the classification prediction model, wherein a warning molecule of an aflatoxin toxigenic strain is one or a combination of more than one of versiconol (VOH), versicolorin B (Ver B), and 5-methoxysterigmatocystin (5-MST).

This invention provides a composition comprising pridopidine or pharmaceutically acceptable salt thereof and at least one of compounds 1-8:

##STR00001##

or a pharmaceutically acceptable salt thereof; and to methods of use thereof.

A method (100) for detecting mycotoxins in organic material, wherein the method (100) comprises of: storing about 2-5 grams of organic material in a temperature less than room temperature; adding a solvent Acetonitrile in the stored organic material to form a first mixture, wherein the first mixture is transferred to a 40-60 ml tubes, centrifuged and shaken for a defined interval; adding 0.5-3 ml of supernatant, 80-120 mg of cyclo-18-carbon (C18) and 200-400 mg of Magnesium sulfate to the first mixture to form a second mixture; and filtering the formed second mixture using a filter syringe to obtain a filtrate, wherein the mycotoxins are detected from the obtained filtrate using Ultra High-Performance Liquid Chromatography (UHPLC) coupled with a mass spectrometer.

The present invention discloses a pollutant generation system. The pollutant generation system includes a pollution source and a pollutant emitter. The pollutant emitter is connected to the pollution source. The pollution source is composed of two gases including air and methane. The flows of the gases are strictly controlled. Then, the gases enter a magnetic bead glass bottle. Due to the disturbance of magnetic beads to the flowing of the gases, the gases are sufficiently disordered, and the two gases are sufficiently mixed by using a spiral tube to generate a uniform and stable pollution source.

The disclosure relates to a recycling chromatography method that includes injecting a sample into a mobile phase flow stream of a chromatography system to create a combined flow stream. The sample includes an API and at least one impurity. The chromatography system includes a first column and a column in series, a first valve in fluid communication with the first and second chromatographic columns, a heater in communication with the first and second chromatographic columns, a fraction collector in fluid communication with the first and second chromatographic columns, and a second valve positioned before the fraction collector. The combined flow stream is recycled from the first chromatographic column to the second chromatographic column and vice versa by switching the first valve until a baseline resolution is achieved to separate the at least one impurity from the API. The at least one impurity is collected in the fraction collector.