Walter Bushnell Research Associate Interview Questions and Answers

Seeking new challenges and opportunities for growth.

• Desire for new challenges and opportunities for growth

• Seeking a more stimulating work environment

• Looking to expand skill set and knowledge

• Company restructuring or downsizing

• Relocation to a new area

A 50 ppm solution contains 50 parts of solute per million parts of solution.

• ppm stands for parts per million.

• It is a measure of concentration.

• In a 50 ppm solution, there are 50 parts of solute per million parts of solution.

• For example, if we have a 1 million mL solution, there would be 50 mL of solute in it.

Mass spectrometry is a technique used to identify and quantify molecules based on their mass-to-charge ratio.

• Electrospray ionization (ESI)

• Matrix-assisted laser desorption/ionization (MALDI)

• Gas chromatography-mass spectrometry (GC-MS)

• Liquid chromatography-mass spectrometry (LC-MS)

• Time-of-flight mass spectrometry (TOF-MS)

UV spectrometry is a technique that measures the absorption or transmission of ultraviolet light by a sample.

• UV spectrometry is based on the principle that different molecules absorb UV light at specific wavelengths.

• It is commonly used in analytical chemistry to determine the concentration of a substance in a sample.

• UV spectrometry can be used to analyze the purity of a compound or identify unknown substances.

• The instr...read more

To prepare 0.1 N HCl and NaOH, you need to calculate the required amount of the respective chemicals and dilute them in water.

• Calculate the molar mass of HCl and NaOH

• Determine the volume of solution needed

• Use the formula: Normality (N) = (Number of equivalents / Volume of solution in liters)

• For 0.1 N HCl, calculate the number of equivalents of HCl and dilute it to the desired volume

• For NaOH, calculate the number of equ...read more

Quality assurance is the process of ensuring that products or services meet the desired level of quality.

• It involves establishing standards and procedures to ensure that products or services meet those standards.

• It includes monitoring and evaluating the quality of products or services to identify areas for improvement.

• It also involves taking corrective action when necessary to address quality issues.

• Examples include co...read more

Recall definitions

• Recall: the ability to retrieve information from memory

• Definition: a statement that explains the meaning of a word or phrase

• Research: the systematic investigation into and study of materials and sources in order to establish facts and reach new conclusions

• Associate: a person who works with others towards a common goal

• Hypothesis: a proposed explanation for a phenomenon

• Experiment: a scientific procedure...read more

The type of HPLC used depends on the specific research requirements and objectives.

• There are several types of HPLC systems available, including reverse phase, normal phase, ion exchange, size exclusion, and affinity chromatography.

• The choice of HPLC system depends on the properties of the analyte, such as polarity, size, charge, and affinity.

• For example, reverse phase HPLC is commonly used for the separation of nonpola...read more

UV detectors and HPLC detectors are used in research to analyze and quantify substances.

• UV detectors are commonly used in UV-visible spectroscopy to measure the absorption of light by a sample at different wavelengths.

• HPLC detectors are used in high-performance liquid chromatography to detect and quantify the components of a mixture.

• Common types of UV detectors include diode array detectors (DAD) and photodiode array d...read more

Matrix in MALDI MS system is a substance used to assist in ionization of the sample for analysis.

• Matrix is a substance that absorbs energy from the laser and transfers it to the sample, causing ionization.

• The choice of matrix depends on the type of sample being analyzed.

• Common matrices include alpha-cyano-4-hydroxycinnamic acid (CHCA) and sinapinic acid (SA).

Column and mobile phase selection is based on the analyte properties and separation goals.

• Consider the analyte's physicochemical properties such as polarity, molecular weight, and stability.

• Choose a column with appropriate stationary phase chemistry (e.g., C18 for hydrophobic compounds).

• Optimize mobile phase composition (solvent ratio, pH, buffer) for desired separation.

• Consider the separation goals (resolution, select...read more