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An effective elucidator is capable of connecting information from multiple sources with the goal of eliminating the inconsistent candidates. In this puzzle, the candidates are molecular formulae (MFs). The previous blog listed 4 potential MFs differing in mass difference and RDBE. The mass difference is not a good filter as the mass differences for the...

Performance of several library search algorithms (against EI mass spectral databases) implemented in commercial software products (ACD/SpecDB, ChemStation, GC/MS Solution, and MS Search) was estimated. Test set contained 1000 mass spectra, which were randomly selected from NIST’08 (RepLib) mass spectral database. It was shown that composite (also known as identity) algorithm implemented in ms search...

Typically, structure elucidation via NMR can be ascribed by a stepwise workflow: 1. a sample is prepared for NMR, 2. the NMR instrument is optimized for data collection, 3. NMR data is acquired, 4. the spectral data is processed, 5. the spectral data is searched/compared to an internal database for possible hits or similarities, 6....

With a monoisotopic mass identified from a mass spectrum, the next step is to fit a molecular formula (or elemental composition) to the unknown. For organic compounds, the starting elements of choice are Carbon, Hydrogen, Oxygen, Nitrogen and sometimes Sulfur. Information from starting material and known derivatives can also help when deciding what elements and...

Reliable in-silico prediction tools for physicochemical properties, ADME characteristics, toxicity endpoints, structure design, and optimization, in one seamless software platform. Toronto, Canada (October 24, 2011)—ACD/Labs is pleased to announce the release of ACD/Labs Percepta, an advanced software platform for accurate in silico ADME/Tox and physicochemical property prediction, at AAPS 2011. The next generation of ACD/Labs...

Increasing importation of food and the diversity of potential contaminants have necessitated more analytical testing of these foods. Historically, mass spectrometric methods for testing foods were confined to monitoring selected ions (SIM or MRM), achieving sensitivity by focusing on targeted ion signals. A limiting factor in this approach is that any contaminants not included on...

A 1H-1H COSY dataset of an unknown structure with protons offers many combinations of atom connectivity. The goal for the elucidator is to assess the correlations and narrow down a set of fragments that support the data. Below is a structural list for 1H to C to 1H connectivities. Absent from the list, heteroatoms such...

Like a COSY experiment, an HMBC dataset offers many combinations of atom connectivity. The goal for the elucidator is to assess each correlation and narrow down a set of fragments that support the data. For every correlation in a 1H-13C HMBC spectrum, an elucidator must decide whether a correlation corresponds to a 2J, 3J or...

When the spectral data is sparse, the list of potential candidate structures can seem endless. The task then becomes sifting through the spectral data as a means to filter the candidates. The purpose of this puzzle is to perform such a task. The following unknown compound with a mass of 380.1 +/- 0.5 Da comprises...