Why Does My DSC Go Below Zero?

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In summary, a DSC can go below zero because it measures the difference in heat flow between a sample and a reference material. This is a normal occurrence in experiments involving phase transitions. However, a DSC cannot go below zero if there is no sample present. Factors such as measurement errors, incorrect calibration, or a malfunctioning instrument can also cause a DSC to go below zero. Interpreting a DSC reading that goes below zero depends on the specific experiment and sample being analyzed.
  • #1
jaejoon89
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My baseline for the DSC goes past zero (below 0 W/g) why would the instrument be doing this?
 
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  • #2
This may be obvious, but: Bad calibration?
 
  • #3
it goes relative to the initial value you put in. the absolute number does not mean much.
 
  • #4
Perhaps you converted from one polymorph to another and a little energy was released? Have you run the same sample twice and noticed the negative value again?
 

Related to Why Does My DSC Go Below Zero?

1. Why does my DSC go below zero?

A DSC (differential scanning calorimeter) measures the heat flow of a sample as it undergoes temperature changes. When the sample absorbs heat, the DSC reading goes up, and when it releases heat, the reading goes down. Therefore, if the sample is losing heat faster than it is absorbing it, the DSC reading can go below zero.

2. Is it normal for a DSC to go below zero?

Yes, it is normal for a DSC to go below zero. In fact, it is a common occurrence and is often seen in experiments involving phase transitions, where the sample is undergoing a change in state from solid to liquid or vice versa.

3. Can a DSC go below zero if there is no sample present?

No, a DSC cannot go below zero if there is no sample present. The DSC measures the difference in heat flow between a sample and a reference material, so without a sample, there is no heat flow to measure.

4. What factors can cause a DSC to go below zero?

Aside from phase transitions, other factors that can cause a DSC to go below zero include measurement errors, incorrect calibration, or a malfunctioning instrument. It is important to carefully follow the manufacturer's instructions and properly calibrate the DSC before conducting experiments.

5. How can I interpret a DSC reading that goes below zero?

Interpreting a DSC reading that goes below zero depends on the specific experiment and sample being analyzed. If the sample is undergoing a phase transition, the DSC can provide valuable information about the enthalpy of the transition. However, if the DSC reading goes below zero unexpectedly, it may indicate a measurement error or an issue with the instrument that should be investigated.

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