Analytical Chemistry Interview Questions
Questions Answers Views Company eMail

please explian me about area normalisation method,diluted standard method,impurity vs impurity and which one has to be selected in method development

Pfizer,

273

How they found 1mL of K.F reagent is equivalent to 5mg of water and if we change the composition of K.F reagent, is it can neutralize more amount of water?

268

How can we calculate offset value pH measurment

Dr Reddys,

148




What is stray light in uv what are units for stray light

Dr Reddys,

173

Colorimtry

Dr Reddys,

171

What are usp limits for theoritical plats,resoution,tailing factor,peak to valley ratio

Dr Reddys,

239

What are usp limits for total impurities,unknown impurity

Dr Reddys,

1 471

how to get accurate result for Residue on evaporation in purified water

221




Why acetonitrile and water are used as extraction solvent when analysis melamine? I thought they are miscible and won't be able to separate...

182

In HPLC calibration, caffeine is used as primary standard for wave length calibration due to caffeine is having dual maxima at 273 & 205 nm and one minima at 245 nm. Any body can give reference of these details from any pharmacopeia (with chapter no.) or any other authentic guideline?

254

could negative ions be produced by bombardment process in mass spectrometry?

134

A ha tc is actual defination of retention time?

177

How to check hplc detecter sensitivity?

Gland Pharma,

184

(0.41)d what is d?

Gland Pharma,

1 323

How to estimate potassium?

137


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Un-Answered Questions { Analytical Chemistry }

what is the structure of DOWEX-50

3565


WHICH STANDARD WE USE IN SILICA ANALYSIS IN SILICA-GEL METHOD FOR SOLID SAMPLE

809


Which std. used for standrdisation of ZnSO4?

987


calibrtion procedue of LC-MS

1205


In HPLC Calibration, On which basis RSD Limit of noise test is fixed (NMT 33.0 % )

1921






How can we calculate "confidence interval" in analytical method validation? Pl. explain with example.

2360


why should we perform dissolution PVT calibration only by UV spectrometer, not by HPLC ?

310


what is lod and loq ?,why use k2cr2o7 , kcl h2so4 in uv calibration ?,why use benzophenone & caffene acetone in hplc calibration ?,what is leading peak in hplc ?why we do the calibration of limit of stry light in hplc & uv ?

2028


what is the limit for KF Factor ,we take factor using water we will found factor between 6 to 7 ,while on KF Reagent bottle mentioned 5 mg/ml water content.if we not use dried methanol it is effect on factor.

656


Why to use propyl paraben in HPLC gradient calibration

293


we are performed SOR for a particular product the limit is -6 to -10.We face particular bathes it is not meeting the specification.we performed diffrent instrument diffrent analyst we are getting diffrent diffrent results.solvent is dimethyl sulfoxide what could be the reasion

432


In performance Check of GC Why Hexadecane Peak is Considered 

1722


WHAT IS DIFFERENCE B/W MALTINGRANG/DSC

1100


Which type of column should i use to check the purity of high molecular weight protein using HPLC reverse phase column chromatography? Hi everyone. I wanna to check the purity of high molecular weight protein (collagen) with MW of ~130 kDa using a HPLC. I know C18

606


What is the formula to determine the concentration of M of a solution given the % transmittance? Use %T = 43.7 as an example.

1257