Chemical Analysis & Techniques Flashcards

In atomic absorption spectroscopy (AAS), what is the primary function of the hollow cathode lamp?

Answer: To emit radiation at the specific wavelength of the analyte element

The hollow cathode lamp emits characteristic radiation at the same wavelength absorbed by the analyte element, enabling selective detection.

Which chromatographic parameter describes the ability of a column to separate two adjacent peaks?

Answer: Resolution (Rs)

Resolution (Rs) quantifies the degree of separation between two adjacent peaks based on their retention times and peak widths.

In potentiometry, what does the Nernst equation relate?

Answer: Electrode potential to ion activity

The Nernst equation relates electrode potential to the logarithm of ion activity, forming the basis for ion-selective electrode measurements.

What is the purpose of an internal standard in quantitative GC analysis?

Answer: To compensate for sample preparation and injection variability

An internal standard corrects for variability in sample preparation, injection volume, and instrument response by normalizing peak areas.

Which technique measures the mass-to-charge ratio of ions to identify chemical compounds?

Answer: Mass spectrometry

Mass spectrometry separates and detects ions based on their mass-to-charge ratio (m/z), providing molecular weight and structural fragmentation data.

In Karl Fischer titration, what species is being quantitatively determined?

Answer: Water content

Karl Fischer titration is a highly specific and sensitive method for determining trace water content in chemical samples.

What does LOD (Limit of Detection) represent in analytical chemistry?

Answer: The lowest concentration distinguishable from the blank signal

LOD is the lowest analyte concentration that can be reliably distinguished from background noise, typically defined as blank signal plus three standard deviations.