Practical Approach for the Determination of Response Factors of Impurities in Drugs by HPLC

Abstract

For the determination of accurate quantity of impurities in the samples authentic impurity standards or response factors at a given wavelength must be known. In the presented work a convenient method for determination of relative response factors of impurities has been described without using an authentic impurities standard. An approach for the determination of response factors of the impurities where impurity standard is physically not available was developed and verified using different approaches. One such method was developed and verified by RP-HPLC using Cosmosil C18 MS-II column at UV 238 nm. Two different approaches were employed and the verification of correctness of approach was done using a known related substance of known response factor.

Measurement of SF6 using gc-ecd: a comparative study on the utilization of CO2-N2 mixture and CH4-ar mixture as a make-up gas

“…Likewise, the calculated response factor from CON (RSD = 0.28 %, n = 5) makeup gas was greater than the corresponding response factor from CAR (RSD = 0.19 %, n = 5). Theoretically, a response factor is the ratio between the concentration of an analyte being analyzed and the detector response to that analyte [32], meaning that the increase in the peak area of SF 6 would increase its response factor. As it can be seen in Table 2, at the same concentration of SF 6 , the obtained peak area of SF 6 using CON (13714.34) is higher than that of CAR make-up gas (9984.72).…”

Profiling of glycosphingolipids with SCDase digestion and HPLC-FLD-MS

“…Fluorescent LC-MS (HPLC-FLD-MS) has the advantage of improved sensitivity and reliable quantification using fluorescently labeled standards, which is not possible with MS-only techniques. [38] Our objective in this study was to extend the advantages of enzymatic GSL degradation to HPLC-FLD-MS using these two complimentary approaches which, in the case of SCDase, maintain the linkage of the glycan headgroup and Sph chain of GSLs. We utilized both methods to profile and quantify GSLs in a mammalian T cell line (Jurkat) and porcine brain tissues.…”

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“…Quantitative NMR is now established as a rapid and generic method for determining concentration, purity, reaction yield, and mixture composition. It was used to determine the assay of DME 15,16,17 . DME was synthesized in the laboratory and its assay was established by quantitative nuclear magnetic resonance (qNMR) comparing intensity of its proton signal with a proton signal of reference compound (THF) at a known concentration.…”