19.2.3 Using Combined Techniques

• What information do individual spectroscopic techniques like NMR, IR, and mass spectrometry provide?

  Specific structural information
• Why do scientists combine complementary techniques in spectroscopy?

  To overcome limitations
• Which combined technique uses NMR to provide structural information and MS to determine molecular mass?

  NMR-MS
• Match the combined technique with its complementary information:

  GC-MS ↔️ Separates and identifies volatile compounds

  LC-MS ↔️ Separates and identifies non-volatile compounds

  NMR-MS ↔️ Gives detailed molecular structure

  IR-Raman ↔️ Identifies functional groups
• What type of compounds does GC-MS identify?

  Volatile compounds
• Combined spectroscopic techniques involve using multiple techniques together to obtain a more complete picture
• Combined techniques can handle complex, unknown samples.


  True
• LC-MS combines liquid chromatography to separate compounds with mass spectrometry
• Match the combined technique with its key principles:

  1️⃣ GC-MS

  2️⃣ Separates volatile compounds using GC and identifies them via MS

  3️⃣ LC-MS

  4️⃣ Separates non-volatile compounds using LC and identifies them via MS

  5️⃣ NMR-MS

  6️⃣ Provides structural information with NMR and confirms mass with MS

  7️⃣ IR-Raman

  8️⃣ Identifies functional groups with IR and provides structural data with Raman
• IR-Raman spectroscopy identifies functional groups and provides complementary structural information.
• Combined spectroscopic techniques provide a deeper understanding of samples by overcoming the limitations of single methods.


  True
• What does NMR-MS provide information about?

  Molecular structure
• Order the steps researchers take when using combined spectroscopic techniques

  1️⃣ Integrate multiple methods

  2️⃣ Obtain a more complete picture

  3️⃣ Overcome limitations of individual techniques
• What two methods are combined in GC-MS?

  Gas chromatography and mass spectrometry
• Combined techniques overcome the limitations of individual methods by combining complementary data.


  True
• Combined techniques enhance analysis by combining chromatographic separation with spectroscopic identification.

  True
• Match the benefit with the technique:

  Information Provided ↔️ Specific, limited

  Sample Complexity ↔️ Limited to simple, known samples

  Reliability of Identification ↔️ Moderate
• What does GC-MS combine to identify compounds?

  Gas chromatography and mass spectrometry
• IR-Raman spectroscopy combines infrared and Raman techniques for complementary structural data.


  True
• LC-MS is used to separate and identify non-volatile compounds.
• NMR-MS combines nuclear magnetic resonance spectroscopy with mass spectrometry.
• What type of information does GC-MS provide for volatile compounds?

  Molecular mass and fragments
• NMR-MS confirms molecular mass while providing detailed structural information.
• LC-MS is used in food safety to analyze non-volatile contaminants.
• In which application is GC-MS used in environmental monitoring?

  Identifying VOCs in air