In bioanalytical method effect of different matrix can cause decrease in sensitivity and affect the assay result and reproducibility.matrix effect and selectivity issues have long been associated with bioanalytical technique.main reason for matrix effect is ion suppression.it is not always possible to remove matrix effect but in those cases it is mandatory to evaluate and quantify matrix effect.it is important to give attention while using matrix during method development.to minimize effect of matrix many method like dilution,reducing iinjection volume,stable isotop labeled internal standard,and others.matrix effect removal is important in automation system.for the viewpoint of regulatory guidelines,in validation determination of matrix effect is essential.the severity of matrix effect is directly dependent on chromatographic performance.it is essential information for method assessment.