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resources:eval:user-guides:circuits-from-the-lab:cn0503:colorimetry [13 Jul 2021 14:14]
Angelo Nikko Catapang
resources:eval:user-guides:circuits-from-the-lab:cn0503:colorimetry [21 Jul 2021 08:48]
Angelo Nikko Catapang
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-====== Optical Platform ​Colorimetry (EVAL-CN0503-ARDZ) ​======+====== Optical Platform: pH Measurement Demo ======
  
-An important water quality indicator for almost any use is the presence ​of dispersed, suspended solids—particles not in true solution ​(often including silt, clay, algae, other microorganisms,​ organic matter, and other minute particles)Turbidity ​is a qualitative characteristic imparted by how these suspended solids obstruct ​the transmittance ​of lightTurbidity is not a direct measure of suspended particles ​in water but rather a measure of the scattering effect such particles have on light.+Colorimetry can be used to determine ​the concentration ​of materials ​in solution ​based on its absorbanceOne application of colorimetry ​is pH measurement with the aid of a coloring reagentThis document details the steps in setting up the EVAL-CN0503-ARDZ for pH measurement.
  
 ===== General Description/​Overview ===== ===== General Description/​Overview =====
  
-The EVAL-CN0503-ARDZ is a four-channel optical platform capable of fluorescence,​ absorbance and scattering measurements. The two middle channels/​light paths are only capable of absorbance and 180-degree scattering measurements. This demo uses one of the side paths for 90- and 180-degree scattering ​measurements.\\ ​+The EVAL-CN0503-ARDZ is a four-channel optical platform capable of fluorescence,​ absorbance and scattering measurements. The two middle channels/​light paths are only capable of absorbance and 180-degree scattering measurements. This demo uses the two paths for absorbance ​measurements ​for two different light wavelengths.\\ 
  
 Measuring pH using colorimetry involves using a chemical reagent or indicator. Different indicators exhibit different color and light absorbance behavior. Some indicators break down into different ions which also exhibit different properties which is why the solution has very different color hues at the ends of the pH range. For this demo we will be using bromothymol blue from either a prepared solution or the API pH Test Kit. Bromothymol blue separates into a weak acid (HIn) and a conjugate base (In). HIn has high absorbance to 430nm light while In has high absorbance at 615nm light. The demo will use light sources with these two wavelengths for the two middle channels.\\ ​ Measuring pH using colorimetry involves using a chemical reagent or indicator. Different indicators exhibit different color and light absorbance behavior. Some indicators break down into different ions which also exhibit different properties which is why the solution has very different color hues at the ends of the pH range. For this demo we will be using bromothymol blue from either a prepared solution or the API pH Test Kit. Bromothymol blue separates into a weak acid (HIn) and a conjugate base (In). HIn has high absorbance to 430nm light while In has high absorbance at 615nm light. The demo will use light sources with these two wavelengths for the two middle channels.\\ ​
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-| //LD2SEL and LD3SEL// ​   | Set to VARD | {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​ld2sel_-_ard.png?​nolink&​400 ​|}} +| //LD2SEL and LD3SEL// ​   | Set to VARD | {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​ld2sel_-_ard.png?​100 |}} {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​ld3sel_-_ard.png?​100 |                              }}                                               | 
-| //​IOSEL// ​               | Set to ARD  | {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​iosel_-_ard.png?​nolink&​400 |}} +| //​IOSEL// ​               | Set to ARD  | {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​iosel_-_ard.png?​nolink&​100 |}}                          | 
-| //​P1.8V// ​               | Shorted ​    | {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​p1.8v_-_ard.png?​nolink&​400 |}}+| //​P1.8V// ​               | Shorted ​    | {{ :​resources:​eval:​user-guides:​circuits-from-the-lab:​cn0503:​p1.8v_-_ard.png?​nolink&​100 |}}                          |
  
 ==== Initial Connection and Setup ==== ==== Initial Connection and Setup ====
resources/eval/user-guides/circuits-from-the-lab/cn0503/colorimetry.txt · Last modified: 21 Jul 2021 08:48 by Angelo Nikko Catapang