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What is a possible consequence of leaving 100% water standing in the detector flow cell?

• Optical enhancement

• Algae growth

• Pressure decrease

• Increased sensitivity

What does "purging" the HPLC pump help achieve?

• Reduces detector noise

• Changes solvents by connecting pump heads to waste

• Increases retention time

• Cleans column end fittings

Which is a characteristic of an overpressure or blockage in the HPLC system?

• Decreased peak height

• No signal

• Sudden increase in system pressure

• Lower resolution

What is the function of solvent inlet filters?

• Regulate flow pressure

• Maintain constant detector wavelength

• Prevent particulate contamination

• Reduce peak tailing

Which maintenance task should be done daily or after changing solvents for smooth pump operation?

• Conditioning

• Leak testing

• Detector calibration

• Degassing

Which of the following best describes peak fronting?

• Wide peaks with a tail

• Asymmetrical peak with leading edge

• Two adjacent peaks combined

• Peak shifted with high baseline

Which factor contributes to "dispersion" in the HPLC system?

• Temperature fluctuations in oven

• Improper injection technique

• Bandspreading from tubing and flow cells

• Air bubbles in detector

Which one is a good practice to avoid microbial growth in mobile phase lines?

• Use only water as mobile phase

• Leave buffers in the system overnight

• Use isopropanol when idle

• Set temperature below 10°C

What may cause peak tailing in a chromatogram?

• Detector saturation

• Column overload or contamination

• Air bubbles in pump

• Column too short

Which statement about Diode Array Detectors (DAD) is correct?

• They cannot detect low concentrations

• They offer low spectral resolution

• They provide excellent spectral sensitivity and resolution

• They are only used for isocratic methods