MASTER Study Guide of all Material- (HPLC, GC-FID, GC-MS, & FAA)

What are the main components of an HPLC system?

Solvent reservoir, degasser, pump, injector/autosampler, column compartment, detector (UV-Vis DAD), waste bottle.

What is the function of the FID detector in GC-FID?

It detects the presence of compounds by measuring the current produced by ions formed when a substance is burned in a flame.

What are key parameters to set in a GC-FID temperature program?

Initial temperature, ramp rate, final temperature and hold, split ratio setting, carrier gas flow.

What must be ensured during sample preparation for HPLC?

Filter through 0.45 μm membrane, dilute to appropriate concentration, match solvent to mobile phase.

How does area under a peak relate to concentration in HPLC analysis?

Area under peak is proportional to concentration.

What is the significance of TIC in GC-MS?

TIC stands for Total Ion Chromatogram and provides a visual representation of all detected ions over time.

What does LOD stand for and what does it represent?

LOD stands for Limit of Detection and represents the smallest signal that can be reliably distinguished from noise.

How is the concentration determined using the Beer’s Law equation?

A = εcl, where A is absorbance, ε is molar absorptivity, c is concentration, and l is the path length.

What does the x-intercept represent in a standard addition graph for FAA?

The x-intercept indicates the concentration of the unknown sample.

What is the primary method of analysis in GC-MS?

Mass spectrum matching to identify compounds.

What is the purpose of High Performance Liquid Chromatography (HPLC)?

To separate and quantify components in liquid samples based on polarity.

What type of column is used in HPLC for reversed-phase separation?

C18 reversed-phase column.

What is the typical flow rate for HPLC?

1.0 mL/min.

What is the calibration curve equation used in HPLC?

y = mx + b.

What must be done to solvents before using them in HPLC?

Degas all solvents to prevent bubble noise.

What is the purpose of Gas Chromatography – Flame Ionization Detection (GC-FID)?

To separate and quantify volatile organic compounds (VOCs) using flame ionization.

What is the carrier gas used in GC-FID?

Helium.

What is the typical injection volume for GC-FID?

1–2 μL.

What should remain lit and stable during GC-FID operation?

The flame.

What is the purpose of Gas Chromatography – Mass Spectrometry (GC-MS)?

To separate and identify volatile compounds by mass-to-charge ratio.

What ionization method is used in GC-MS?

Electron Ionization (EI) at 70 eV.

What is a key reminder when using GC-MS?

Use solvent delay to protect the detector.

What is measured in Flame Atomic Absorption Spectroscopy (FAA)?

Metal ions in aqueous samples via element-specific light absorption.

What equation is associated with Beer’s Law in FAA?

Absorbance = molar absorptivity × concentration × path length.

What should be matched in all standards and samples during FAA?

The acid matrix.

What is indicated by a match factor >900 in GC-MS?

Strong confidence in identification.

What does HPLC stand for?

High-Performance Liquid Chromatography

What is the purpose of the C18 column in HPLC?

It retains nonpolar analytes longer.

What is the mobile phase used in HPLC?

Water + Methanol.

What does the output of HPLC indicate regarding peak area?

Peak area is proportional to concentration.

What type of injector is used in HPLC?

Split Injector controls how much sample enters the column.

What does FID stand for in GC-FID?

Flame Ionization Detector.

What is the primary function of the FID detector?

It detects ionized carbon species.

In GC-FID, what does the output peak area indicate?

Peak area is proportional to the amount of volatile organics.

What ionization method is used in GC-MS?

Electron Ionization (EI) at 70 eV.

What does TIC stand for in the context of GC-MS?

Total Ion Chromatogram.

What is the function of the HCl lamp in FAA?

It matches specific metal wavelengths.

What is the output measurement related to in FAA?

Absorbance is proportional to metal concentration in ppm.

What are the different separation bases of HPLC, GC-FID, GC-MS, and FAA?

HPLC relies on polarity, GC-FID and GC-MS rely on volatility, and FAA involves atomization.

What is the required injection volume for HPLC?

5–20 μL.

What should you do if there are no peaks in your HPLC results?

Check λmax and sample preparation.

What is the critical adjustment needed for the burner in FAA?

Burner height and fuel/air ratio.

What is the significance of the match score greater than 900 in GC-MS?

It indicates strong confidence in the identification.

How do you correct matrix interference in FAA?

Use standard addition.

What does broad or tailing peaks in HPLC suggest, and how can it be fixed?

It suggests clean column or flow adjustments.

How can you establish a calibration curve in HPLC?

By plotting area vs concentration.

What are the four main steps in HPLC analysis?

Sample → Injection → Detection → Data Interpretation

What type of column is used in HPLC for separation?

C18 column (nonpolar)

What method is used for detection in HPLC?

UV-Vis DAD at λmax

How is concentration determined in HPLC?

Using area under the peak and calibration curve.

In GC-FID, what is the typical sample volume injected?

1–2 μL via split injector.

What type of detection method is used in GC-FID?

Detection by ion current in Hydrogen-Air flame.

What is the relationship between peak area and concentration in GC-FID?

Peak area is proportional to concentration.

What kind of solvent is typically used for sample preparation in GC-MS?

Volatile solvent (e.g., hexane).

What happens to the sample after it is injected into the GC in GC-MS?

It is ionized by Electron Ionization (EI) at 70 eV and fragmented.

What is the purpose of the Quadrupole mass filter in GC-MS?

To achieve m/z separation of ionized fragments.

Where can the extracted mass spectra be matched?

In the NIST library.

What key step follows atomization in the flame for metal analysis?

Emission of specific wavelengths for the respective metal.

How is concentration calculated in the method for aqueous metal samples?

Using standard addition or calibration.