Entering the Formula for a Stable Isotope Labeled Compound in SCIEX OS Software|質量分析計・LC-MS/MSシステムのSCIEX


日付: 10/02/2019
カテゴリー: SCIEX OS

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For research use only. Not for use in diagnostic procedures.


Answer

To enter the formula for a stable-isotope-labeled compound in the Components tab of a processing method in SCIEX OS software, some specific rules must be followed. When entering the formula, the atomic mass of the isotope is added before the single letter chemical abbreviation of the element, and then the total number of atoms of each isotope follows the chemical symbol. For example, the chemical formula for a stable isotope labeled version of C24 H45 N12 O8 P3 Cl containing three atoms of deuterium, one carbon-13, one nitrogen-15 and one oxygen-18 would be C23 13C 2H3 H42 N11 15N 18O O7 P3 Cl. The spaces in the formula between each isotope and element are critical. When the formulas are entered into the Chemical Formula column in the processing method, the mass in the Precursor (Q1) Mass (Da) column is automatically calculated and the mass value appears in the column (see figure).

stable isotope label

Posted: Aug 11, 2023

This works well for the Chemical formula and in Positive mode, but how do you make the adduct change in Negative mode such that I can have 2H subtracted from the mass? The options provided using the same nomenclature are actually just [M-H2]2+, not actually [M-2H]+ as the Adduct column allows.