What is a function of combustion unit in GC-C-IRMS?
Burns sample at high temperature to obtain suitable analyte gas for feeding into GC
Separates isotopes
Cools down the sample
Burns sample at high temperature to obtain suitable analyte gas for feeding into MS
Carbon originating from C3 plants has more negative 13C value than carbon originating from C4 plants. What does that mean? (There may be one or more correct answers)
C3 plants are on an average less rich in carbon
C3 plants contain on an average less 13C than C4 plants
C3 plants contain on an average more 13C than C4 plants
Isotope fractionation is more extensive in C4 plants than in C3 plants
Isotope fractionation is more extensive in C3 plants than in C4 plants
What is the major difference between GC-C-IRMS and EA-IRMS?
GC-C-IRMS measures isotope ratios in single compounds, EA-IRMS in bulk samples
GC-C-IRMS measures isotope ratios in bulk samples, EA-IRMS in single compounds
GC-C-IRMS is used to measure isotopes in gases, EA-IRMS in solid samples
What is the δ13C related to?
Ratio of 14C to 12C
Ratio of 12C to 13C
Ratio of 13C to 12C
What are the main elements for which isotope measurements are carried out with GC-C-IRMS? (Select all that apply)
H
Sr
C
N
O
S
Fe
What is/are the key issue(s) for any type or IRMS? (There may be one or more correct answers)
Ability to measure very accurately the ratios of signal intensities originating from ions with different isotopic compositions
Ability to measure very accurately atomic masses of the isotopes
Ability to measure very accurately m/z ratios of ions formed during combustion processes
Ability to measure very accurately ratios of isotope abundances
Ability to have as high m/z resolution as possible
Which of the following statements are true for GC-C-IRMS? (There can be one or more correct answers)
The analytes must be volatile
Specific compound’s isotopic ratios can be measured
Faraday plates are used to detect ions
The sample is usually in solid form
