Analytical Chemistry Interview Questions And Answers

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

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

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.

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

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.

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.

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.

Isotopes of H2O, D2O

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

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.

Standard deviation tells about the widely spread out of the
measured analytical data points. Highly precised
measurements are less standard deviation.

The H is the height of the main peak and the h is the lowest
height of a peak in the range of X5 the main peak (around
the amin peak)

The chemical substances that pair each other, to form
complexes. These can use for stabilization of one of the
molecule that is more active or to colorifying etc.

#Base line is nothing but the detectors response to the
mobile phase.(gc,hplc)

#Base line should be stable to start a run.

#Un stabilized base line is called as base line noise.

#Base line noise is of many types..
1)Cyclic base line
2)Synchorinise noise
3)Asynchorinise noise
4)Base line drift
5)Spikes
6)Negative peaks
7)No peaks

#Base line noise is attributed due to mobile phase,sample,
system problems.leaks in the system,temperature variations
in lab etc..

calibration is also one of the system
suitability test,whether the system working satisfactory or
not physically so when you do the calibration for pH meter
with standard pH buffer solution (which is from NIST-it may
accurate solution for actual pH)and once if your instrument
has calibrated,you can cross verify your insrument against
those pH buffer solution (NIST) and the acceptable range is
+/- 0.02 then you can conclude for ?

once if temperature raises the pH will decrease and its not
all cases

NO

When analyte gives linear response then only we can use area normalization. When analyte response is to high and saturated in chromatograph, for this condition we can use diluted standard.

it is having both regulatory and domestic markets

nitrogen

Purity is only area normalization.
Rs is calculated by using std and rrf

C8 column have more polar than C18. and it has 8 carbon atoms.

I DO NOT KNOW

5 mg of water consuming 1 ml of KF reagent.

Just you want to know about that please just refer your SOP (STANDARD OPERATING PROCEDURE)

That sample converted chromofore by derivitisation technique and going to analysis