Analytical Chemistry Interview Preparation Guide
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Analytical Chemistry job interview questions and answers guideline. Lean Analytical Chemistry and get preparation for the job of Analytical Chemistry

27 Analytical Chemistry Questions and Answers:

1 :: What is deference between the working standard and reference standard?

Reference std is like USP,EP std , in this std we get COA
including results of Potency by HPLC , NMR & XRPD data.
whenever there is requirement of w.std preparation first we
have get API rawmaterial from warehouse & we check assay ,
water content or LOD & Related substances aganist reference
std . Some times we are doing analysis in duplicate & get
mean value.then we decide final assay or potency value &
it's validity one year

2 :: How do we fix the sample concentaryion in hplc method development. what is the basis?

IF ALL IMPURTITIES AT SPEC LEVEL ARE MEETING S/N RATIO MORE
THAN 60 AT THAT PARTICULAR CONCENTRATION AS WEL AS NO
COLUMN OVERLOAD.

3 :: Suppose we prepared pH buffer solution in lab.and calibrate against NIST solution, and same shall going to used upto 30 days. is it possible to stable pH and apperance? suggest?

pH OF THE BUFFER SOLUTION WILL BE CHANGE, AS DUE TO PRESENCE OF NITROGEN CONTAINING SUBSTANCES AND ALSO DUE TO MICROBIAL GROWTH. BUT IF STORED AT 4 DEGREE CENTI. IT MAY USED TO SOME EXTENT.

4 :: What is rs test why we are perfoming rs test?

RS stands for related substance, means by-products upon
completion of reaction, or the unreacted portion present in
the product. RS testing help us to identify the adequate
quantitiy of these by-products or unreacted part.
More over RS help us during the stability study to know any
significant change in the nature of product during long
storage in various climatic conditions

5 :: What is difference between silica used in TLC and HPLC column?

Tlc is called thin layer chromatography. The simple technique works on the principle of adsorption, where as HPLC is a sophisticated technique works on partition principle.

6 :: What is use of acetonitrile compare to methanol in RP-HPLC Method development?

ACN is highly polar as compare to Methanol So provide Better
resolution for many compound and it has property to form
hydrogen bond so provide better selectivity.

7 :: How to know HPLC column performance?

Check for the number of plates that it maintains stady all
over the run , check the SST at avery run that cpmplies the
acceptance criterias of the method.

8 :: What is heavy water?

Isotopes of H2O, D2O

9 :: What is quality controle?

quality control means to maintain the quality of product by
calculating their content ,different physical parameters,as
per their specification IP/BP/USP/EP/JP

10 :: When we get Moisture content by KF higher than by LOD, what does this indicate?

KF titration is the most accurate method in analysing
moisture content. But it is coastlier and maintaince is too
high. So in analysis of moisture content an alternative
experiment is Loss on Drying(LOD), which gives approximate
moisture value present in the given substance.