A method for identifying converters from tobacco seedling population. The method includes: 1) sowing and cultivating tobacco seeds to be identified for 45-55 days; sampling a plurality of leaf disks from each of 45-55 days old seedlings; 2) incubating the plurality of leaf disks of each seedling in a sealed container at 37° C. for 10-12 hours, thereby obtaining a plurality of incubated tobacco leaves of each seedling; 3) immersing the plurality of incubated tobacco leaves of each seedling in an extractant, extracting alkaloids and obtaining an extract of each seedling; 4) analyzing the amounts of nicotine and nornicotine in the alkaloids extract of each seedling; and 5) automatically recognizing peaks of the alkaloids extract of each seedling, and calculating the percent nicotine conversion (PNC) and the pseudo percent nicotine conversion (PPNC).

Methods of assessing purity of cytisine using gradient chromatography at multiple wavelengths is provided herein.

The invention relates to a standard solution for inverse gas chromatography and/or surface energy analysis; a volumetric container for preparing such a standard solution; a method of preparing such a standard solution for inverse gas chromatography and/or a surface energy analysis and a method of probing a solid sample. The standard solution comprises a series of three or more compounds of increasing carbon chain length of general formula (I): R—X wherein: for the three or more compounds R is a series of alkyl, a series of alkenyl or a series of alkynyl groups of increasing carbon chain length; and for all three or more compounds X is H, OH, CO.sub.2H, C(O)H, C(O)CH.sub.3, NH.sub.2, SH or halogen; and the relationship between carbon chain length and volume of the compounds of increasing carbon chain length of general formula (I) is determined by the following formula.

A process for identifying an unknown compound in a sample includes matching a peak in a primary Fourier Transform Infrared spectral region of the sample spectrum with reference spectra in the same spectral region to generate an initial list of potential candidates, based, for example on goodness of fit criteria. The initial list can be reduced by retention time information and/or global peak matching techniques that analyze the sample spectrum in regions outside the primary region.

A process for identifying an unknown compound in a sample includes matching a peak in a primary Fourier Transform Infrared spectral region of the sample spectrum with reference spectra in the same spectral region to generate an initial list of potential candidates, based, for example on goodness of fit criteria. The initial list can be reduced by retention time information and/or global peak matching techniques that analyze the sample spectrum in regions outside the primary region.

Disclosed is a method of measuring tacrolimus levels in a subject. In exemplary embodiments, the method comprises the steps of: collecting oral fluid from the subject; homogenizing the oral fluid; combining the homogenized oral fluid with a precipitating solvent; separating oral fluid components on a liquid chromatography column by gradient elution with a mixture of a solvent A and a solvent B, wherein the solvent A is about 2 mM ammonium acetate/0.1% (v/v) formic acid in water and solvent B is about 2 mM ammonium acetate/0.1% (v/v) formic acid in MeOH and wherein the amount of solvent B is increased from about 50% (v/v) to about 98% (v/v); and determining amount of tacrolimus in the oral fluid by mass spectrometry.

A gas chromatographic method for detecting a marker compound in a fuel by (a) introducing a sample of fuel into a first capillary column coated with a stationary phase based on polydimethylsiloxane and allowing the sample to flow through the first column to produce a first effluent; (b) allowing the first effluent to pass through a detector and identifying a retention time range in it which includes a retention time of the marker compound; (c) introducing only a portion of the first effluent stream which is within the retention time range into a second capillary column coated with either (i) an ionic sorbent or (ii) a polyethylene glycol, and allowing said portion to flow through the second capillary column to produce a second effluent stream; and (d) allowing the second effluent to pass through a detector; wherein the marker compound has formula Ar(R.sup.2).sub.m(OR.sup.1).sub.n and is present in the fuel at a level from 0.01 ppm to 100 ppm.

A reference sample for analysis that is optimal for calibration of a pyrolysis gas chromatograph-mass spectrometer and with which precise calibration is always possible by preventing a reference substance from evaporating is provided. A reference sample sheet 1 is provided by distributing a target component or target components with a uniform normality in a base made of a high polymer material, and the reference sample sheet 1 is rolled up so that the target component or target components can be prevented from evaporating from the reference sample sheet 1 even in the case where a component has volatility. A reference sample for calibration of a pyrolysis gas chromatograph-mass spectrometer can be easily, quickly, and efficiently collected by punching out the reference sample sheet 1 using a micro-puncher 2.

A method of analyzing phenylhydrazine content in a 3-methyl-1-phenyl-2-pyrazolin-5-one active pharmaceutical ingredient includes obtaining a first measured value by measuring a phenylhydrazine content of a standard solution including phenylhydrazine or a salt thereof, a first acidic water and a first water-soluble organic solvent and having a phenylhydrazine concentration of 0.01 μg/mL to 10 μg/mL, obtaining a second measured value by measuring a phenylhydrazine content in a sample solution including a 3-methyl-1-phenyl-2-pyrazolin-5-one active pharmaceutical ingredient, a second acidic water and a second water-soluble organic solvent, and detecting a phenylhydrazine content in a 3-methyl-1-phenyl-2-pyrazolin-5-one active pharmaceutical ingredient based on the first measured value and second measured value. The first acidic water is hydrochloric acid, and/or an aqueous acetic acid solution, the first water-soluble organic solvent is acetonitrile and/or methanol, the second acidic water is hydrochloric acid, and/or an aqueous acetic acid solution, and the second water-soluble organic solvent is acetonitrile and/or methanol.

The present disclosure relates to a nanoscale thin film structure and implementing method thereof, more specifically nanoscale thin film structure of which target structure is designed with quantized thickness and a method to implement the nanoscale thin film structure by which the performance of the manufactured nanodevice can be implemented the same as the designed performance, thereby applicable to high sensitivity high performance electronic/optical sensor devices.