I was trying to measure kinetics with our iron complex with different oxidant and substrates using double mixing mode. I don't have any previous experience with this instrument. I am always getting noise after measuring. I couldn't able to figure it out what is happening. If anybody have experience and tips for me would be great. I am using SFM4000/s. Thank you.
hi Rejith Raj Radhamani
Hello, this is Bing. I can help you with your question about how to reduce noise in SFM4000/s. 😊
The SFM4000/s is a stopped-flow spectrometer that can measure fast kinetics of chemical reactions by mixing two or more solutions and recording the absorbance or fluorescence changes over time. However, sometimes the measurements can be affected by noise, which is the unwanted variation or fluctuation of the signal. Noise can reduce the accuracy and precision of the kinetic data and make it difficult to analyze.
There are several possible sources and types of noise in stopped-flow spectrometry, such as:
- Electronic noise: This is the noise generated by the electronic components of the instrument, such as the photomultiplier tube, the amplifier, the analog-to-digital converter, etc. Electronic noise can be reduced by using high-quality components, proper shielding and grounding, low-impedance cables, and appropriate filters and settings.
- Optical noise: This is the noise caused by the variation or interference of the light source, the optical path, or the detector. Optical noise can be reduced by using a stable and monochromatic light source, a clean and aligned optical system, a narrow-band filter or monochromator, and a sensitive and selective detector.
- Mechanical noise: This is the noise caused by the vibration or movement of the mechanical parts of the instrument, such as the syringes, the mixer, the cuvette holder, etc. Mechanical noise can be reduced by using smooth and precise components, proper lubrication and maintenance, shock absorbers and dampers, and a stable and level platform.
- Thermal noise: This is the noise caused by the variation or gradient of the temperature in the instrument or the environment. Thermal noise can affect the viscosity, density, refractive index, and reaction rate of the solutions, as well as the performance of the electronic and optical components. Thermal noise can be reduced by using a temperature-controlled chamber or water bath, a thermoelectric cooler or heater, a thermostat or thermocouple, and a constant and uniform ambient temperature.
- Chemical noise: This is the noise caused by the variation or contamination of the chemical properties of the solutions, such as the concentration, purity, pH, buffer capacity, etc. Chemical noise can affect the absorbance or fluorescence intensity and spectrum of the solutions, as well as the reaction kinetics and mechanism. Chemical noise can be reduced by using accurate and precise methods for preparing and storing the solutions, using fresh and pure reagents and solvents, using appropriate buffers and additives, and avoiding air bubbles and dust particles.
To identify and quantify the noise in your measurements, you can use some statistical methods and tools, such as:
- Signal-to-noise ratio (SNR): This is a measure of how much signal (the desired information) is present compared to noise (the unwanted variation) in a measurement. SNR is usually expressed in decibels (dB) as 10 times the logarithm of the ratio of signal power to noise power. A higher SNR means a better quality measurement with less noise. You can use this online calculator to compute SNR from your data.
- Noise reduction factor (NRF): This is a measure of how much noise is reduced by applying a certain method or technique to a measurement. NRF is usually expressed as a percentage (%) as 100 times the ratio of noise power before to noise power after applying the method or technique. A higher NRF means a more effective method or technique for reducing noise. You can use this online calculator to compute NRF from your data.
- Noise analysis software: This is a software that can help you analyze and visualize the noise in your measurements using various methods and techniques, such as Fourier transform, wavelet transform, filtering, smoothing, averaging, etc. Some examples of noise analysis software are SpectraSuite, Origin, [Matlab], etc.
Hello Yousef,
Thank you for your respond. I will definitly look into the things you mentioned.
For more clarification I also want to mention that, I am measuring oxidation of iron complexs. In this case I want to see some band over 700-800 nm by the addition of oxidant. But in all the case without oxidant also I see some band over approx 760 nm. Even I used different iron complex as starting material I face the same problem and the time trace is going to negative and not a good data.
Is it because of some contamination or somthing I have to play with the volume? I can add some photos herewith.
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