Terminology — The plotted output signal versus time obtained after a GC run is called a what?
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AChromatograph
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BChromatogram
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CChromatophore
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DGraph
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ESpectrogram
Answer
Correct Answer: Chromatogram
Explanation
Introduction / Context:Precise terminology matters in analytical chemistry. Students commonly confuse the instrument, the separation medium, and the recorded output. This question clarifies the correct term for the time-dependent detector signal produced by a chromatographic run.
Given Data / Assumptions:
- The instrument is the chromatograph.
- The separation technique is chromatography.
- The recorded signal versus time (or volume) is the chromatogram.
Concept / Approach:A chromatogram displays peaks corresponding to analytes eluting from the column. Retention times and peak areas/heights are extracted from the chromatogram for identification and quantification.
Step-by-Step Solution:
Run the GC method and collect detector signal vs time.Observe peaks at characteristic retention times.Integrate peak areas for quantitation; compare tR for identification.Recognize the resulting plot as the chromatogram.Verification / Alternative check:Software exports, reports, and standards consistently label the plotted output as the chromatogram (e.g., “save chromatogram as .cdf/.raw”).
Why Other Options Are Wrong:
- Chromatograph: the instrument, not the plot.
- Chromatophore: a biological pigment cell, irrelevant to GC.
- Graph/spectrogram: generic or spectroscopy-specific terms, not standard GC nomenclature.
Common Pitfalls:Mixing up instrument and output terms; always report “chromatogram” for the trace.
Final Answer:Chromatogram.