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resources:eval:user-guides:circuits-from-the-lab:cn0503:fluorescence [17 May 2021 17:20] – Angelo Nikko Catapang | resources:eval:user-guides:circuits-from-the-lab:cn0503:fluorescence [21 Jan 2022 21:46] (current) – Angelo Nikko Catapang | ||
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- | ====== Optical Platform Fluorescence Measurement | + | ====== Optical Platform: Fluorescence Measurement |
Fluorescence occurs when the electrons of certain chemical compounds are excited by beam of light causing them to emit light at a different and typically longer wavelength. The intensity of the emitted fluorescent light is linear for a broad range of concentration of the substance. The method of measuring fluorescence intensity to obtain the concentration of the material is advantageous over standard colorimetry due to its specificity and resistance to noise. Since only the target chemical compound emits light at a different wavelength, using a detector or optical filter which detects or passes narrowband light centered at that wavelength decreases interference from the source or incident light. | Fluorescence occurs when the electrons of certain chemical compounds are excited by beam of light causing them to emit light at a different and typically longer wavelength. The intensity of the emitted fluorescent light is linear for a broad range of concentration of the substance. The method of measuring fluorescence intensity to obtain the concentration of the material is advantageous over standard colorimetry due to its specificity and resistance to noise. Since only the target chemical compound emits light at a different wavelength, using a detector or optical filter which detects or passes narrowband light centered at that wavelength decreases interference from the source or incident light. | ||
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===== General Description/ | ===== General Description/ | ||
- | The EVAL-CN0503-ARDZ is a four-channel optical platform capable of fluorescence, | + | The [[ADI>CN0503]] is a four-channel optical platform capable of fluorescence, |
The demo shows how directly measuring fluorescent light from tonic water indicates the presence and level of quinine. Directing 365nm wavelength light to tonic water causes the quinine in the solution to fluoresce blue light at around 450nm. The intensity of light that fluoresces from quinine is proportional to its concentration at low levels. | The demo shows how directly measuring fluorescent light from tonic water indicates the presence and level of quinine. Directing 365nm wavelength light to tonic water causes the quinine in the solution to fluoresce blue light at around 450nm. The intensity of light that fluoresces from quinine is proportional to its concentration at low levels. | ||
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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 {{ : |
* Tonic water from commercial brands | * Tonic water from commercial brands | ||
===== Setting Up the EVAL-CN0503-ARDZ ===== | ===== Setting Up 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: | ||
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<note important> | <note important> | ||
- | - Connect the 365nm LED Board and the 615nm LED Board to LED1.\\ {{ : | + | - Connect the 365nm LED Board and the 615nm LED Board to LED1.\\ {{: |
- | - Place the fluorescent filter into the slot in front of PD1B. and set the jumper connection as below: | + | - Place the fluorescent filter into the slot in front of PD1B. and set the jumper connection as below: |
^ Jumper Header | ^ Jumper Header | ||
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- 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 EVAL-ADICUP3029 to the EVAL-CN0503-ARDZ 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) and wait for the main window to open.\\ {{: |
- | - 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.\\ {{: |
- | - In the settings window, select the correct COM Port of the device and connect (see Software User Guide for help)\\ {{ : | + | - In the settings window, select the correct COM Port of the device and connect (see {{ : |
- Load the configuration file for Fluorescence Measurement ({{ : | - Load the configuration file for Fluorescence Measurement ({{ : | ||
- | - Configure the settings for path 1 with the desired name (e.g. Quinine), set wavelength to 365.0, and select measurement type: Fluorescence.\\ {{ : | + | - Configure the settings for path 1 with the desired name (e.g. Quinine), set wavelength to 365.0, and select measurement type: Fluorescence.\\ {{: |
- | - Add empty cuvette/s (or filled with distilled water) to the cuvette holder assembly, and insert to path 1. Set the jumper connection of P1ASEL temporarily to 0DEG. This uses the transmit photodiode directly in the path of light from LED1 to check measure the intensity of light source.\\ {{ : | + | - Add empty cuvette/s (or filled with distilled water) to the cuvette holder assembly, and insert to path 1. Set the jumper connection of P1ASEL temporarily to 0DEG. This uses the transmit photodiode directly in the path of light from LED1 to check and measure the intensity of the light source.\\ {{: |
- Click Optimize LED. This properly sets the LED current in the path so that the light intensity measured by the photodetector is close to 50%. | - Click Optimize LED. This properly sets the LED current in the path so that the light intensity measured by the photodetector is close to 50%. | ||
- | - Return the P1ASEL jumper connection to 90DEG and click Okay here and on the settings window to go back to the main. Remove the empty cuvette or distilled water sample.\\ {{ : | + | - Return the P1ASEL jumper connection to 90DEG and click Okay here and on the settings window to go back to the main. Remove the empty cuvette or distilled water sample.\\ {{: |
- | - Place a cuvette with filled with tonic water sample | + | - Place a cuvette with filled with tonic water sample |
- | - Select path 1, set display mode to INS1, and press Start Measurement. The concentration of quinine in g/L will be shown in a live plot as shown below.\\ For quick demo purposes, the system was configured in path 1, by default, | + | - Select path 1, set display mode to INS1, and press Start Measurement. The concentration of quinine in g/L will be shown in a live plot as shown below.\\ {{: |
+ | <note important> | ||
===== Computing Concentration ===== | ===== Computing Concentration ===== | ||
- | - Optionally, you can write g/L to the primary unit field of path 1. These are just labels and are not required.\\ {{ : | ||
+ | The CN0503 measures the intensity of the fluorescent light through a right angle photodiode and the intensity of the incident light through a reference photodiode. A polynomial approximation for computing quinine concentration can be modeled using the ratios of the two intensities measured from samples of known values.\\ | ||
+ | <note important> | ||
+ | - The ratio of the fluorescent light intensity and incident light intensity is calculated using the CN0503 firmware and is called the **absolute ratio (ARAT)**. | ||
+ | - The computation of the ARAT is configurable through software in reverse polish notation (RPN). The variable naming format for the measured light intensities is shown below:\\ < | ||
+ | <light path>< | ||
+ | where: | ||
+ | <light path> = A for path 1, B for path 2, C for path 3, D for path 4 | ||
+ | < | ||
+ | </ | ||
+ | - **Optionally**, | ||
+ | - Using samples with known quinine concentration, | ||
+ | - A 3rd order polynomial approximation can be obtained from the trendline of the x-y scatter plot of the data.\\ {{: | ||
+ | <note important> | ||
+ | The polynomial approximation is applied to the CN0503 using the **DEFX INS1** or **DEFX INS2** command (See the [[resources: | ||
+ | ===== Reference Links ===== | ||
+ | * [[resources: | ||
+ | * [[resources: | ||
+ | * {{ : |