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:

Table of Contents:

Analytical Chemistry Interview Questions and Answers
Analytical Chemistry Interview Questions and Answers

1 :: How to establish relative response factor for hplc.
why it is required?

Actually RRF establishment required For Relatives Substances
Why because in Rs Sample having so many components like impurities,Degradents and main Analytes etc..so all components does not have same wavelength but we are fix one particular wavelength for all peaks. so inthat wavelength some peak response high and some peak response low.so that reason only we are established RRF and impurities also expensive so every time we can't purchase.so once established the RRF that factor used for RS calculation

2 :: How we choose the mobile phase for method development..?

it depend on the solubility of analyte whether it is soluble in polar or non polar solvent apart from that retention time, capacity factor to prepare suitable mobile phase.

3 :: How can we detect a compound in hplc which does not have any chromofore?

That sample converted chromofore by derivitisation technique and going to analysis

4 :: How to calibration of the uv spectroscopy and its test?

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

5 :: Why karl fisher factor is 5 ?

5 mg of water consuming 1 ml of KF reagent.

7 :: What is the difference between c8 and c18 hplc column?

C8 column have more polar than C18. and it has 8 carbon atoms.
Purity is only area normalization.
Rs is calculated by using std and rrf

9 :: In the gas chromatography what is used carrier gasand make up gas?

nitrogen

10 :: What is similarity factor and its use in api strength?

it is having both regulatory and domestic markets

11 :: In rs method development when we are going area normalization method to dilute standard method?

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.

13 :: IN pH CALIBRATION,CALIBRATION IS DONE FOR pH METER OR ELECTRODE?HOW WILL YOU JUDGE THAT THE METER TO BE CALIBRATED WITH 4,7,9.2 BUFFERS?EXPLAIN TEMPERATURE EFFECTS ON pH?

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

14 :: Explain What is a base line?

#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..

15 :: WHAT IS USE OF ION PAIR REAGENTS?

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.

16 :: How to calculate signal to noise ratio by this formula 2H/h where h from where and how to measure?

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)

17 :: What is Standard deviation?

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

18 :: 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.

19 :: 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

20 :: What is heavy water?

Isotopes of H2O, D2O

21 :: 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.

22 :: 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.

23 :: 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.

24 :: 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

25 :: 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.