Low Level Detection
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Raman is able to discern a low level presence in many mediums. Listed below are some examples of low level measurements. |
Nitrate added to Aqueous Solution
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The spectral response from trace concentrations of sulfate in an aqueous solution are displayed to the right, and the observed spectral responses were initially background corrected. A PI-200-HP spectrograph containing high performance lenses and a deep depleted CCD was used for this study. The change in peak intensity is easily distinguishable down to the single digit ppm range. |
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Comparisons between the actual and predicted nitrate concentrations in an aqueous solution are displayed on the right. The standard deviation from the (actual – predicted) concentrations was 0.5 ppm and the linear relationship had a correlation coefficient of 0.999. |
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Trace Detection of Benzene in a Hydrocarbon
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The spectral response from trace concentrations of benzene in isopropyl alcohol are displayed to the right, and the observed spectral responses were initially background corrected. A PI-200 spectrograph containing high performance lenses was used for the benzene monitroing. Lower detection limits, down to the 5 ppm range, could be easily obtained by using our high performance CCD, increasing laser power, or increasing the sample integration time. |
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The figure to the right displays the linear relationship between the benzene peak intensity and the benzene’s concentration in a hydrocarbon. The linear relationship has a correlation coefficient of 0.9987. |
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Trace Detection of Propylene Glycol in Water
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The spectral response from trace concentrations of propylene glycol in an aqueous solution are displayed to the right, and the observed spectral responses were initially background corrected. A PI-200-HP spectrograph containing high performance lenses and a deep depleted CCD was used for this study. The change in peak intensity is easily distinguishable down to the double digit ppm range. |
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Comparisons between the actual and predicted propylene glycol concentrations in an aqueous solution are displayed on the right. The standard deviation from the (actual – predicted) concentrations was 0.0038 vol% and the linear relationship had a correlation coefficient of 0.999. |
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