Analytical Scientist

Analytical Scientist Interview Questions and Answers

Updated 16 Jul 2025

Asked in Dr. Reddy's

2d ago

Q. Who to prepare buffers,difference btwn np-hplc,rp-hplc, uses of potentiometric titrantions

Ans.

Preparing buffers, differences between NP-HPLC and RP-HPLC, and uses of potentiometric titrations.

Buffers are prepared by mixing a weak acid and its conjugate base or a weak base and its conjugate acid.
NP-HPLC separates non-polar compounds while RP-HPLC separates polar compounds.
Potentiometric titrations are used to determine the concentration of an unknown solution by measuring the potential difference between two electrodes.
Potentiometric titrations are commonly used in the...read more

Asked in Dr. Reddy's

3d ago

Q. Limits for nitrosamine impurities and regulatory aspects

Ans.

Nitrosamine impurities have limits set by regulatory bodies to ensure safety of pharmaceutical products.

Nitrosamines are potentially carcinogenic impurities found in some pharmaceutical products.
Regulatory bodies such as FDA and EMA have set limits for nitrosamine impurities in pharmaceutical products.
The limits vary depending on the type of product and the route of administration.
For example, the FDA has set a limit of 96 ng/day for nitrosamine impurities in ranitidine produ...read more

Asked in Dr. Reddy's

3d ago

Q. Current approaches on nitrosamine impurities

Ans.

Current approaches on nitrosamine impurities

Analytical techniques such as LC-MS and GC-MS are commonly used to detect and quantify nitrosamine impurities in pharmaceuticals
Regulatory agencies have set limits on the acceptable levels of nitrosamine impurities in drugs
Manufacturers are required to conduct risk assessments and implement control measures to prevent nitrosamine contamination
Some common approaches to mitigate nitrosamine impurities include changing manufacturing pr...read more

Asked in Dr. Reddy's

5d ago

Q. What is the ESI and APCI difference? What is the way of development of method for Impurities??

Ans.

ESI and APCI are ionization techniques used in mass spectrometry. Method development for impurities involves identification, quantification, and validation.

ESI (Electrospray Ionization) and APCI (Atmospheric Pressure Chemical Ionization) are ionization techniques used in mass spectrometry.
ESI is suitable for polar and ionic compounds, while APCI is suitable for nonpolar and less polar compounds.
ESI involves the formation of ions by the interaction of a sample with charged dro...read more

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Asked in Dr. Reddy's

3d ago

Q. Quadrapoles functioning

Ans.

Quadrapoles are used in mass spectrometry to filter ions based on their mass-to-charge ratio.

Quadrapoles use radio frequency and direct current voltages to selectively filter ions.
They are composed of four parallel rods that create a quadrupole electric field.
Ions with a specific mass-to-charge ratio will oscillate within the field and pass through the filter.
Quadrapoles are commonly used in tandem mass spectrometry for peptide sequencing and protein identification.

Asked in Dr. Reddy's

3d ago

Q. Q trap system in quadrapoles

Ans.

Q trap system is a type of mass spectrometer that uses triple quadrupole technology with an added linear ion trap for enhanced sensitivity and selectivity.

Q trap system is used for targeted quantification and identification of small molecules in complex matrices.
It combines the benefits of triple quadrupole technology with an added linear ion trap for enhanced sensitivity and selectivity.
It allows for multiple reaction monitoring (MRM) and enhanced product ion (EPI) scans for...read more