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resources:eval:user-guides:circuits-from-the-lab:cn0503:colorimetry [06 Apr 2021 08:40] – Angelo Nikko Catapang | resources:eval:user-guides:circuits-from-the-lab:cn0503:colorimetry [21 Jul 2021 08:48] (current) – Angelo Nikko Catapang | ||
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- | ====== Optical Platform | + | ====== Optical Platform: pH Measurement Demo ====== |
Colorimetry can be used to determine the concentration of materials in a solution based on its absorbance. One application of colorimetry is pH measurement with the aid of a coloring reagent. This document details the steps in setting up the EVAL-CN0503-ARDZ for pH measurement. | Colorimetry can be used to determine the concentration of materials in a solution based on its absorbance. One application of colorimetry is pH measurement with the aid of a coloring reagent. This document details the steps in setting up the EVAL-CN0503-ARDZ for pH measurement. | ||
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The following is a list of items needed in order to replicate this demo. | The following is a list of items needed in order to replicate this demo. | ||
- | * EVAL-CN0503-ARDZ, completely assembled (see Hardware User Guide) | + | * [[ADI>CN0503]], completely assembled (see [[resources: |
- | * EVAL-ADICUP3029 with firmware (see Software User Guide) | + | * [[ADI>EVAL-ADICUP3029]] with firmware (see [[resources: |
- | * Host computer with CN0503 software (see Quick Setup Guide) and Microsoft Excel (Optional for generating your own measurement curve) | + | * Host computer with CN0503 software (see {{ : |
- | * Bromothymol blue or API pH Test Kit (https:// | + | * Bromothymol blue or API pH Test Kit [[https:// |
* pH Buffer Solutions (Optional for calibration) | * pH Buffer Solutions (Optional for calibration) | ||
* Common household chemicals for testing (caustic soda, baking soda, vinegar, and distilled water) | * Common household chemicals for testing (caustic soda, baking soda, vinegar, and distilled water) | ||
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===== Setting the EVAL-CN0503-ARDZ ===== | ===== Setting the EVAL-CN0503-ARDZ ===== | ||
- | Before starting with these steps, please check the Hardware User Guide for the steps to assembling the EVAL-CN0503-ARDZ. Additionally, | + | Before starting with these steps, please check the [[resources: |
Configure the onboard jumper shunt connection as below: | Configure the onboard jumper shunt connection as below: | ||
- | ^ Jumper Header | + | ^ Jumper Header |
- | | //LD2SEL and LD3SEL// | + | | //LD2SEL and LD3SEL// |
- | | // | + | | // |
- | | // | + | | // |
+ | |||
+ | ==== Initial Connection and Setup ==== | ||
- Connect the 430nm LED Board and the 615nm LED Board to LED2 and LED3, respectively.\\ {{ : | - Connect the 430nm LED Board and the 615nm LED Board to LED2 and LED3, respectively.\\ {{ : | ||
- | - Connect the EVAL-ADICUP3029 to the EVAL-CN0503-ARDZ and connect a microUSB-to-USB cable from the board to the host computer. | + | - Connect the [[ADI>EVAL-ADICUP3029]] to the [[ADI>CN0503]] and connect a microUSB-to-USB cable from the board to the host computer. |
- | - Run the software (using python scripts or the executable) and wait for the main window to open.\\ {{ : | + | - Run the software (using python scripts or the executable, see the {{ : |
- Click the Gear icon at the top right of the window to open Settings.\\ {{ : | - Click the Gear icon at the top right of the window to open Settings.\\ {{ : | ||
- | - Select the correct COM Port of the device and connect (see Software User Guide for help)\\ {{ : | + | - Select the correct COM Port of the device and connect (see {{ : |
- Load the configuration file for pH Measurement ({{ : | - Load the configuration file for pH Measurement ({{ : | ||
- Configure the settings for path 2 and 3 with the desired name, set wavelengths to 430 and 615, respectively, | - Configure the settings for path 2 and 3 with the desired name, set wavelengths to 430 and 615, respectively, | ||
- Add empty cuvette/s (or filled with distilled water) to the cuvette holder assembly and insert to path 2 and 3, and click Optimize LED for each path. This properly sets the LED current in these paths so that the light intensity is close to 50%.\\ {{ : | - Add empty cuvette/s (or filled with distilled water) to the cuvette holder assembly and insert to path 2 and 3, and click Optimize LED for each path. This properly sets the LED current in these paths so that the light intensity is close to 50%.\\ {{ : | ||
- | | + | |
+ | ==== Setting a Baseline Ratio ==== | ||
+ | The baseline ratio is used to remove small factors introduced to the measurement such as by the optical glass elements, e.g. beam splitter, lens, and filters. The baseline ratio is the ARAT value of a known setups such as with an empty cuvette or distilled water sample where it is known that the ratio of incident and transmitted light should be approximately 1. This value is used as a reference for successive measurements which will be defined as the relative ratio RRAT. | ||
+ | |||
+ | | ||
- Click on Start Measurement and note the average value on the graph. Remember the empty cuvette or distilled water sample should still be in the path. The average value will be used as the baseline ratio for this path.\\ {{ : | - Click on Start Measurement and note the average value on the graph. Remember the empty cuvette or distilled water sample should still be in the path. The average value will be used as the baseline ratio for this path.\\ {{ : | ||
- Click on Stop Measurement (Repeat the two previous steps for path 3) then, click on the settings icon on the top right corner to bring back the settings and click on Advanced to bring up the another window.\\ {{ : | - Click on Stop Measurement (Repeat the two previous steps for path 3) then, click on the settings icon on the top right corner to bring back the settings and click on Advanced to bring up the another window.\\ {{ : | ||
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- Optionally, you can write pH to the primary unit field of path 2 and path 3. These are just labels and are not necessary.\\ {{ : | - Optionally, you can write pH to the primary unit field of path 2 and path 3. These are just labels and are not necessary.\\ {{ : | ||
- Click Okay here and on the settings window to go back to the main. Remove the empty cuvette/s or distilled water sample/s. The device is now ready to measure pH. | - Click Okay here and on the settings window to go back to the main. Remove the empty cuvette/s or distilled water sample/s. The device is now ready to measure pH. | ||
+ | |||
+ | ==== Performing a pH Measurement ==== | ||
+ | |||
- Place a prepared cuvette with the test sample to either path 2 and path 3. Check the Preparing Test Sample section on how to prepare a cuvette with the test sample and indicator.\\ {{ : | - Place a prepared cuvette with the test sample to either path 2 and path 3. Check the Preparing Test Sample section on how to prepare a cuvette with the test sample and indicator.\\ {{ : | ||
- | - Select either path 2 or path 3, set display mode to INS1, and press Start Measurement. For quick demo purposes, the system was configured in path 3, by default, to use the measurement curve shown below. Check the Setting Measurement Curve section on how to set your own using spreadsheets and the advanced settings\\ {{ :resources: | + | - Select either path 2 or path 3, set display mode to INS1, and press Start Measurement.\\ {{ : |
+ | <note important> | ||
===== Preparing Test Samples ===== | ===== Preparing Test Samples ===== | ||
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===== Generating a Measurement Curve ===== | ===== Generating a Measurement Curve ===== | ||
- | The pH measurement curve is a function which models the relationship of the absorbance of either the weak acid or conjugate base of the reagent used to the pH of the solution. You can generate your own measurement curve using samples | + | The pH measurement curve is a function which models the relationship of the absorbance of either the weak acid or conjugate base of the reagent used to the pH of the solution. You can generate your own measurement curve using samples |
- | <note important> | + | <note important> |
+ | Using Microsoft Excel, it is easy to generate the measurement curve by following the steps outlined below. | ||
+ | - Create list of the RRAT measurements of each sample and the known pH in 2 different columns.\\ {{ : | ||
+ | * To get the RRAT measurement of a solution, select either path 2 or 3 and RRAT in the display units, and click Start Measurement\\ {{ : | ||
+ | * Use the average or median of the measurement values. | ||
+ | - Create a scatter plot of of the two columns with RRAT as the X-variable and pH as the y-Variable\\ {{ : | ||
+ | - Create a trend-line for the scatter plot and select the polynomial option with an order of up to 5. Also, check the box at the bottom to Display Equation on chart\\ {{ : | ||
+ | - Use the equation of the trendline and input the coefficients to the CN0503 using the Command field in the Advanced settings. See the [[resources: | ||
+ | ===== Reference Links ===== | ||
+ | * [[resources: | ||
+ | * [[resources: | ||
+ | * {{ : |