A method for identifying and analyzing dissolved organic nitrogen of different sources in wastewater includes extracting DON in wastewater to obtain a DON extract, detecting mass spectrum peaks in the DON extract, pre-processing the spectral data of the wastewater sample; constructing a network relationship of the substance reaction in the wastewater sample; screening the substance reaction relationship of DON; and determining different sources of DON.

This invention provides an isolated compound having the structure: ##STR00001##
or a salt thereof, processes for making the same and to compositions comprising pridopidine with these compounds.

An automated radiopharmaceutical production and quality control system includes a particle accelerator, a radiopharmaceutical micro-synthesis subsystem, and quality control subsystem. The micro-accelerator of the improved biomarker generator is optimized for producing radioisotopes useful in synthesizing radiopharmaceuticals in quantities on the order of multiple unit doses, allowing for significant reductions in size, power requirements, and weight when compared to conventional radiopharmaceutical cyclotrons. The radiopharmaceutical micro-synthesis subsystem encompasses a small volume chemical synthesis system comprising a microreactor and/or a microfluidic chip and optimized for synthesizing the radiopharmaceutical in small quantities, allowing for significant reductions in processing time and in the quantity of radioisotope required. The automated quality control subsystem is used to test the composition and characteristics of the radiopharmaceutical to ensure that it is safe to inject.

Disclosed is a detection method for N-nitrosodimethylamine (NDMA) impurities, comprising: (1) obtaining a test solution containing a sample to be tested; and (2) detecting the test solution by means of gas chromatography-mass spectrometry to determine the content of an N-nitrosodimethylamine impurity in the sample. The method provided in the present invention has a good separating effect, a wide linear range, a high sensitivity and a good method durability, and can detect the content of N-nitrosodimethylamine (NDMA) in the sample rapidly and effectively.

The invention provides a process of controlling the impurities of clindamycin hydrochloride, comprising a step of purifying said clindamycin hydrochloride by two-phase high performance liquid chromatography, wherein the chromatographic conditions are as follows: the detection wavelength is 200-220 nm; the column temperature is 20-40° C.; the flow rate is 0.8-1 ml/min; Mobile phase A: 0.025 mol/L potassium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; and gradient elution is performed. The method of controlling impurities of the invention can solve the problem of the interference by excipients and the problem of the separation of many impurities at the same time. It also provides an effective method for setting quality standard of impurities in such a formulation.

An embodiment of an analysis system can include an initial multi-port valve, at least one intermediate multi-port valve, a further multi-port valve, and a time-of-flight mass spectrometer (TOF-MS). The initial multi-port valve can be configured to receive a sample. The at least one intermediate multi-port valve can be fluidly connected to the initial multi-port valve and configured to receive the sample from the initial multi-port valve. A given intermediate multi-port valve can have an ion-exchange column associated therewith. The given intermediate multi-port valve can be configured selectably to one of direct the sample through the ion-exchange column associated therewith (in a speciation mode) or bypass the ion-exchange column (in an infusion mode). The further multi-port valve can be fluidly connected with the at least one intermediate multi-port valve and configured to receive the sample from therefrom. The time-of-flight mass spectrometer (TOF-MS) can be fluidly connected to the further multi-port valve.

A sorbent tube holder (100) for securing a sorbent tube (10) in position in a fluid-flow system, the sorbent tube holder (100) comprising: an mounting element (126) having first and second opposed ends (126a, 126b) which define a tube mounting axis (A-A); at least one fastener (128) in communication with the mounting element (126) for providing a releasable tube retaining force; at least one sorbent tube (10) engaged with the mounting element (126); and a holder frame (130) to which the mounting element (126) is attached to prevent or limit movement of the mounting element (126) perpendicular to the tube mounting axis. A method of preventing or limiting unintentional damage to a sorbent tube, and a portable tube holder are also provided.

Methods for characterizing host-cell proteins in a sample matrix are provided.

The detection of minute amounts of components that have been undetectable due to an influence of a mobile phase or reagents or the like added to the mobile phase is realized in LC-MS. At the outset, blank measurement is executed, and an m/z value M.sub.BG of a background signal derived from a mobile phase or the like is extracted on a mass spectrum obtained by the blank measurement (S2-S4). An analysis method is then created that executes scanning measurement in a plurality of divided m/z ranges in which the m/z value M.sub.BG of the background signal has been excluded from a predetermined m/z range. An LC/MS analysis of the target sample is executed according to the analysis method (S5-S6). When a total ion chromatogram (TIC) is created from data obtained by the LC/MS analysis, influence of the background signal hardly appears in the TIC, and the base line is lowered.

Automated systems and methods for obtaining of the concentration of impurities in a liquid ethylene oxide product stream are shown and described. The systems and methods employ remote injection and flash vaporization of small volumes of liquid ethylene oxide into a carrier gas to minimize polymerization of the ethylene oxide and accumulation of polymerized ethylene oxide. Ethylene oxide peaks are diverted from the gas chromatograph effluent detector to stabilize baseline signal errors and avoid errors in the calculation of an impurity with an adjacent retention time peak. The systems and methods may be used for feedback, feedforward, dynamic matrix, and/or model-based predictive control of ethylene oxide purity. The systems and methods reduce lag times and errors associated with relying on laboratory analyses to make process adjustments.