Accurate Mass

Accurate mass analyses are intended to provide additional confirmation on the empirical formula of an analyte. When used in a publication it is best to use the guidelines from the Journal of Organic Chemistry. The following is a paragraph from the 'Instructions to Authors':
 
Accurate mass measurements should be performed at a mass resolution sufficient to minimize interferences. The reported molecular formulas and Calcd values should include any added atoms (usually H or Na). The ionization method and mass analyzer type should be reported. The number of potential molecular formulas within a given mass range centered on a measured (Found) value increases rapidly with molecular mass. A Found value within 0.003 m/z unit of the Calcd value of a parent-derived ion, together with other available data (including knowledge of the elements present in reactants and reagents) is usually adequate for supporting a molecular formula for compounds with molecular masses below 1000 amu. Higher accuracy may be needed for compounds of higher mass, and for compounds of uncertain synthetic or biosynthetic origin, such as isolated natural products and their derivatives.
 
The term High Resolution Mass Spectrometry (HRMS) is an historical misnomer for accurate mass measurement. Resolution is a measure of the ability to separate one mass from another but provides no information on the calibration of the mass scale of the instrument and therefore as to whether any data obtained is in fact accurate.
 
Accurate mass determination are conducted by the facility staff because these analyses require additional care in terms of sample concentration, instrument calibration and the use of a lock mass to account for intra-analysis instrument variation. For the most part accurate mass measurements are conducted within 1 - 2 days (or less) of the receipt of a sample. 
 
The form for sample submission can be downloaded here and is available in the Facility. 
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