Selection of internalstandard in montelukast method development by lc-msms?

The selection of an internal standard (IS) in the LC-MS/MS method development for montelukast is crucial for ensuring accurate quantification and compensation for variability in sample preparation and instrument response. An ideal IS should possess similar chemical properties to montelukast, such as similar polarity and ionization behavior, while being structurally distinct to avoid interference. Common choices include deuterated analogs of montelukast or chemically similar compounds that do not occur in biological samples. The IS should also be easily detectable and have a stable response across the expected concentration range.