Actually I said something wrong. Transmitance = 0% means infinity absorbance, which is impossible. Transmitance below 0% there is no physical and mathematical meaning. Like I said before, you should check your equipment and the setup of your analysis. Good luck.
Actually I said something wrong. Transmitance = 0% means infinity absorbance, which is impossible. Transmitance below 0% there is no physical and mathematical meaning. Like I said before, you should check your equipment and the setup of your analysis. Good luck.
It's impossible. By the Beer-Lambert Law, if your transmitance is below 0%, this means that you have an infinity absorbance. You should check your equipment, the baseline correction, the zero correction and the setup configuration of your analisys.
It's impossible. By the Beer-Lambert Law, if your transmitance is below 0%, this means that you have an infinity absorbance. You should check your equipment, the baseline correction, the zero correction and the setup configuration of your analisys.
During your calibration you took the "dark reference" measurement. That represents values that would be subtracted from your spectrum as dark noise. However, the dark noise signal in your instrument fluctuates over time and may get to a values lower than the "dark reference" you told your instrument to subtract each time you take a measurement. Now, if your sample does not transmit at a particular wavelength/wavelength range, and your instrument subtracts a higher dark reference value from a reduced dark noise, you end up getting negative transmittance. I would take the transmittance in those areas you got negative values as zero.
During your calibration you took the "dark reference" measurement. That represents values that would be subtracted from your spectrum as dark noise. However, the dark noise signal in your instrument fluctuates over time and may get to a values lower than the "dark reference" you told your instrument to subtract each time you take a measurement. Now, if your sample does not transmit at a particular wavelength/wavelength range, and your instrument subtracts a higher dark reference value from a reduced dark noise, you end up getting negative transmittance. I would take the transmittance in those areas you got negative values as zero.
1) base line correction 2) or some impurities ( not cleaned instrument or sample holder or cuvette not cleaned for long time) 3) change the quette to check it 4) dilute the polymer solution then check any difference 5) increase transmission or absorption range in UV SPECTRA
1) base line correction 2) or some impurities ( not cleaned instrument or sample holder or cuvette not cleaned for long time) 3) change the quette to check it 4) dilute the polymer solution then check any difference 5) increase transmission or absorption range in UV SPECTRA
You have a problem with the baseline correction. At your blank sample you have maybe impurities which already absrob at this region.
You have a problem with the baseline correction. At your blank sample you have maybe impurities which already absrob at this region.
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Actually I said something wrong. Transmitance = 0% means infinity absorbance, which is impossible. Transmitance below 0% there is no physical and mathematical meaning. Like I said before, you should check your equipment and the setup of your analysis.
Good luck.
Actually I said something wrong. Transmitance = 0% means infinity absorbance, which is impossible. Transmitance below 0% there is no physical and mathematical meaning. Like I said before, you should check your equipment and the setup of your analysis.
Good luck.
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It's impossible.
By the Beer-Lambert Law, if your transmitance is below 0%, this means that you have an infinity absorbance. You should check your equipment, the baseline correction, the zero correction and the setup configuration of your analisys.
It's impossible.
By the Beer-Lambert Law, if your transmitance is below 0%, this means that you have an infinity absorbance. You should check your equipment, the baseline correction, the zero correction and the setup configuration of your analisys.
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Hello dear A= 2 -log %T Therefore the % transmitance is between 0 and 100 %. I am agree with Gustavo
Hello dear A= 2 -log %T Therefore the % transmitance is between 0 and 100 %. I am agree with Gustavo
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Thank you for this input.
Thank you for this input.
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Dear Nsuhoridem I. Jackson ;
Do you have any reference for: "I would take the transmittance in those areas you got negative values as zero." ?
Dear Nsuhoridem I. Jackson ;
Do you have any reference for: "I would take the transmittance in those areas you got negative values as zero." ?
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During your calibration you took the "dark reference" measurement. That represents values that would be subtracted from your spectrum as dark noise. However, the dark noise signal in your instrument fluctuates over time and may get to a values lower than the "dark reference" you told your instrument to subtract each time you take a measurement. Now, if your sample does not transmit at a particular wavelength/wavelength range, and your instrument subtracts a higher dark reference value from a reduced dark noise, you end up getting negative transmittance. I would take the transmittance in those areas you got negative values as zero.
During your calibration you took the "dark reference" measurement. That represents values that would be subtracted from your spectrum as dark noise. However, the dark noise signal in your instrument fluctuates over time and may get to a values lower than the "dark reference" you told your instrument to subtract each time you take a measurement. Now, if your sample does not transmit at a particular wavelength/wavelength range, and your instrument subtracts a higher dark reference value from a reduced dark noise, you end up getting negative transmittance. I would take the transmittance in those areas you got negative values as zero.
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Thank you very much for your valuable answers.
Thank you very much for your valuable answers.
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1) base line correction
2) or some impurities ( not cleaned instrument or sample holder or cuvette not cleaned for long time)
3) change the quette to check it
4) dilute the polymer solution then check any difference
5) increase transmission or absorption range in UV SPECTRA
1) base line correction
2) or some impurities ( not cleaned instrument or sample holder or cuvette not cleaned for long time)
3) change the quette to check it
4) dilute the polymer solution then check any difference
5) increase transmission or absorption range in UV SPECTRA
More
VOTE