This version is outdated by a newer approved version.
This version (11 May 2021 17:18) is a draft.
Approvals: 0/1
This version (11 May 2021 17:18) is a draft.Approvals: 0/1
This is an old revision of the document!
Table of Contents
Optical Platform Fluorescence Measurement (EVAL-CN0503-ARDZ)
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.
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 either of the two side 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.
While bromothymol blue exhibits the most change in color in the 6 to 8 pH range, buffer solutions with known pH solutions can be used to set up the measurement/calibration curve. The demo uses the CN0503 GUI and details steps to set-up the pH measurement curve using a spreadsheet.
Demo Requirements
The following is a list of items needed in order to replicate this demo.
- EVAL-CN0503-ARDZ, completely assembled (see Hardware User Guide)
- EVAL-ADICUP3029 with firmware (see Software User Guide)
- Host computer with CN0503 software (see Quick Setup Guide) and Microsoft Excel (Optional for generating your own measurement curve)
- Bromothymol blue or API pH Test Kit (https://apifishcare.com/product/ph-test-kit)
- pH Buffer Solutions (Optional for calibration)
- Common household chemicals for testing (caustic soda, baking soda, vinegar, and distilled water)
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, please check the Software User Guide for the steps in setting up the firmware and the Quick Setup Guide for running the software. This demo assumes that you already have an assembled board with a working firmware already programmed on the EVAL-ADICUP3029 and a ready-to-run software in the host computer.
Configure the onboard jumper shunt connection as below:
| Jumper Header | Setting |
|---|---|
| LD2SEL and LD3SEL | Set to VARD |
| IOSEL | Set to ARD |
| P1.8V | Shorted |
resources/eval/user-guides/circuits-from-the-lab/cn0503/fluorescence.1620746310.txt.gz · Last modified: 11 May 2021 17:18 by Angelo Nikko Catapang