International Journal of Pharmaceutical and Bio-Medical Science ISSN(print): 2767-827X, ISSN(online): 2767-830X Volume 02 Issue 01 January 2022 Page No: 10-17 DOI: https://doi.org/10.47191/ijpbms/v2-i1-02, Impact Factor: 5.374 10 Volume 02 Issue 01 January 2022 Corresponding Author: Tapan Kumar Pal Internal Standard an Important Analyte Use in Drug Analysis by Liquid Chromatography Mass Spectrometry- An Article Pallab Mandal 1,2,3 , Soumya Chakraborty 1,4 , Rakesh Bera 1,5 , Sanmoy Karmakar 2,3 , Tapan Kumar Pal 1,2,3 1 TAAB Biostudy Services, Jadavpur, Kolkata 700032, India 2 Bioequivalence Study Centre, Department of Pharmaceutical Technology, Jadavpur University Kolkata, India 3 Department of Pharmaceutical Technology, Jadavpur University , Kolkata, India 4 College of Pharmaceutical Sciences, Mohuda, Berhampore, Orissa, India 5 Bharat Technology, Uluberia, Howrah, India 1. INTRODUCTION A known amount of compound which is added to an unknown sample known as an internal standard. In analytical and bio- analytical chemistry, calibration curve (standard curve) used in a method for determining the concentration of an unknown sample by comparing a set of standard known concentrated sample. Calibration curve use for instrumental calibration but another approach for uses of calibration curve for standardization by mixing the standard into the unknown sample, which giving an internal standard. This substance added in a constant amount to a blank and standard sample in an analysis and compensate for both systematic errors like matrix effect of the solvent, effect is equal forBoth of standard and the analyte, the ratio is unaffected and random errors like fluctuation of the instrument are expected that the ratio of the signals of the standard and analyte does not change. [01] The limitation of internal standards is hard to search a suitable internal standard, because the internal standard must have a signal that is similar to the analyte but if different enough it can distinguish by theinstrument. The concentration of the internal standard is constant in the sample and this concentration ofthe internal standard should not suppress or enhance the signal of the analyte. [02] Chromatography is the separation of the chemical components or analyte in a mixture which contain oneliquid phase called mobile phase and other is solid phase called stationary phase. Among various others chromatography techniques one of the technique is liquid chromatography mass spectrometry. Here alsorequire individual standards and reproducible conditions enable peak identification by retention time and internal standard also require for quantitation purpose. Internal standard is important for quantitation in High performance liquid chromatography and gas chromatography, liquid mass spectrometry. So, internal standard is a very important analyte for quantitation of ABSTRACT ARTICLE DETAILS Internal standard is an external compound which is mixed with targeted analytical solution and matrix as a constant concentration and use for preparing calibration standard curve by using ratio of analyte area and internal standard area with analyte concentration and internal standard concentration. This calibration curve used for quantification of unknown concentration of anlayte of interest. This article provide necessary information about internal standard like its selection procedure, characterization, types and response factor , to all analyst who are connected with drug analysis. This article is more important and I think first article which focuses a clear idea about internal standard use in drug analysis. KEYWORDS: LC-MS/MS, Internal standard, Drug analysis ABBREVIATION LC-MS: Liquid Chromatography Mass Spectrometry; RSD: Relative standard deviation; RF: Response factor; RRF: Relative response factor; RT: Retention time; RRT: Relative retention time; RTS: Retention time shifts; Published On: 11 January 2022 Available on: https://ijpbms.com/