Physical Interference
Physical Interference - Related Videos
08:41
Interference and Diffraction
0 Views •
2023
Source: Yong P. Chen, PhD, Department of Physics & Astronomy, College of Science, Purdue University, West Lafayette, IN Interference and diffraction are characteristic phenomena of waves, ranging from water waves to electromagnetic waves such as light. Interference refers to the phenomenon of when two waves of the same kind overlap to give an alternating spatial variation of large and small wave amplitude. Diffraction refers to the phenomenon of when a wave passes through an aperture or...
02:18
Interference and Diffraction
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2020
Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a resulting wave with enhanced amplitude is produced. This is known as constructive interference. In this case, the two waves interacting are in phase with each other. Alternatively, if the two waves coincide and interact in a way such that the trough of one wave coincides with the peak of the other (in an out of phase manner), the resultant wave will...
01:23
RNA Interference
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2019
RNA interference (RNAi) is a process in which a small non-coding RNA molecule blocks the post-transcriptional expression of a gene by binding to its messenger RNA (mRNA) and preventing the protein from being translated. This process occurs naturally in cells, often through the activity of genomically-encoded microRNAs. Researchers can take advantage of this mechanism by introducing synthetic RNAs to deactivate specific genes for research or therapeutic purposes. For example, RNAi could be used...
09:06
RNA Interference in Ticks
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Cited by 49 •
2011
A method for RNA interference (RNAi) by injection of dsRNA into unfed ticks is described. RNAi is the most widely used gene-silencing technique in ticks where the use of other methods of genetic manipulation has been limited.
05:21
General Approach to the Physical Exam
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2023
Source: Jaideep S. Talwalkar, MD, Internal Medicine and Pediatrics, Yale School of Medicine, New Haven, CT The examination of the body is fundamental to the practice of medicine. Since the Roman Empire, physicians have described the connection between alterations in function of specific parts of the body and specific disease states and have sought to further scientific understanding to improve bedside diagnosis. However, in this modern age of increasing technology within medical diagnostics, it...
FAQs
Viscosity and surface tension can change how efficiently a sample enters the instrument and forms an aerosol. Density and particle size also influence transport and the physical behavior of the introduced material. Because these properties can vary between a sample and its calibration standards, the instrument may produce different analyte responses even though the analyte itself has not chemically changed.
Physical interference can affect several linked stages rather than a single measurement point. A sample may be aspirated differently, nebulized into a different aerosol, or atomized with altered efficiency before the signal is detected. These changes modify the amount of material reaching the detection stage, so the measured response no longer represents the analyte concentration in the same way as the standard.
Calibration standards establish the response used to interpret an unknown. If their viscosity, surface tension, density, particle size, or transport behavior differs from the sample, the calibration may not describe the sample’s measurement conditions. The resulting error is therefore linked to response comparability, not necessarily to a chemical change in the analyte.
Matrix matching makes calibration standards more physically similar to samples, reducing differences in how they are transported and measured. Dilution can also lessen the influence of sample properties by changing the matrix conditions presented to the instrument. Analysts choose these approaches to improve agreement between standard responses and sample responses.
Internal standards provide a reference for evaluating measurement behavior within an analysis. They can help account for response differences caused by the sample’s physical properties rather than by a change in analyte chemistry. This strategy is one option for improving accuracy when complex samples do not behave like the calibration standards.
Standard-addition calibration is useful when the sample matrix causes its response to differ from that of ordinary calibration standards. By incorporating the sample into the calibration approach, analysts can reduce the effect of response mismatch associated with physical properties. This method is therefore valuable for improving results when matrix matching or dilution alone does not adequately address the interference.
The issue is important in atomic spectroscopy because aspiration, nebulization, atomization, and signal detection are central measurement stages. The same principle also matters in other instrumental methods whenever sample transport or related physical behavior affects the response. Managing it supports accurate and reliable results in analyses involving complex samples.