Chemical Analysis & Techniques Flashcards
7 cards from real CPC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Chemical Analysis & Techniques flashcards as text
In solid-phase extraction (SPE), what is the purpose of the conditioning step?
Answer: To activate and wet the sorbent to ensure reproducible retention
Conditioning wets and activates the SPE sorbent with an appropriate solvent to ensure consistent and reproducible analyte retention during sample loading.
Which electroanalytical technique applies a linearly varying potential to a stationary electrode and measures the resulting current?
Answer: Linear sweep voltammetry
Linear sweep voltammetry scans the electrode potential linearly with time and records the current response, producing peaks at characteristic potentials for electroactive species.
What is the primary advantage of using tandem mass spectrometry (MS/MS) over single-stage MS?
Answer: Improved selectivity by fragmenting and re-analyzing specific precursor ions
MS/MS selects a specific precursor ion in the first stage, fragments it, then analyzes the fragment ions in the second stage, dramatically improving selectivity and reducing matrix interference.
In thermal analysis, what does differential scanning calorimetry (DSC) measure?
Answer: Heat flow difference between sample and reference as a function of temperature
DSC measures the heat flow difference between a sample and an inert reference as both are subjected to a controlled temperature program, revealing thermal transitions like melting, crystallization, and glass transition.
Which technique is best suited for the simultaneous multi-element analysis of trace metals in water samples?
Answer: ICP-MS
ICP-MS provides simultaneous multi-element detection at ultra-trace levels (ppt range) with high sensitivity and wide dynamic range, making it ideal for complex water matrices.
What is the purpose of derivatization in chromatographic analysis?
Answer: To convert analytes into more detectable or better-separated forms
Derivatization chemically modifies analytes to improve their volatility, detectability (e.g., adding chromophores), or chromatographic behavior by altering polarity or functional groups.
In method validation, what does 'robustness' assess?
Answer: The method's insensitivity to small, deliberate variations in experimental parameters
Robustness evaluates how resistant a method is to small variations in parameters such as pH, temperature, or mobile phase composition, indicating reliability under normal operating conditions.