An interference is a substance, other than the assayed material, that can be measured by the chosen analytical method or that can prevent the assayed material from being measured. Interferences cause erroneous analytical results.
Table of Contents
What is analyte interference?
Analytical interference is defined as the effect of a substance present in the sample that alters the correct value of the result.
Which are types of interference that can happen during sample analysis?
Interferences are classified as endogenous or exogenous. Endogenous interference originates from substances present in the patient’s own specimen. Exogenous interferences are substances introduced into the patient’s specimen.
What is positive interference in chemistry?
Positive interferents are those materials and conditions which add to a target gas’s concentration measurement so the gas detector’s measurement reading is higher than the actual concentration value of the target gas.
What causes chemical interference?
Chemical interference occurs when an analyte is not totally decomposed in flame. There is less atoms present, and therefore a reduced absorbance of the analyte. Compound Formation. Compounds cannot be broken down in flame.
How are chemical interferences avoided?
a) A releasing agent is a substance that reacts preferentially with a chemical interference, thus preventing its interaction with the analyte. b) A protective agent is a chelating agent that prevents chemical interferences by forming stable but volatile combinations with the analyte.
How can we eliminate interference in an experiment?
If the sample components cause the multiplicative (specific) interferences, they can be eliminated by another calibration approachโthe standard addition method (SAM) [2, 3].
Why do we need to separate interfering substances during a chemical analysis?
impurities in a sample may interfere with the analysis of the substance of primary interest. Thus, in the analysis of trace concentrations of metals in rivers, organic substances can cause erroneous results. These interferences must be removed prior to the analysis.
What are interfering substances?
Any substance, other than the ion being measured, whose presence in the sample solution affects the measured emf of a cell. Interfering substances fall into two classes: ‘electrode/electrochemical’ interferences and ‘chemical’ interferences.
How can spectral interference be prevented?
Avoidance: ICP-OES Several modern ICP instruments have the capability of avoiding the spectral interference by going to another line. Many instruments can make measurements simultaneously on several lines for 70+ elements in the same time it used to take to make a measurement on a single line/element combination.
What are the main interfering substances of the PT test?
For this review, we defined interference as “the effect of a substance present in the sample that alters the correct value of the result, usually expressed as concentration or activity, for an analyte.” There are four major endogenous compounds that consistently interfere with laboratory results: hemoglobin, bilirubin, …
What happen in case of interference?
interference, in physics, the net effect of the combination of two or more wave trains moving on intersecting or coincident paths. The effect is that of the addition of the amplitudes of the individual waves at each point affected by more than one wave.
What is interference and its types?
What is interference and what kinds of interference exist? Interference is when two waves collide with each other. There are two types of interference: constructive and destructive interference.
Do you mean by interference?
Interference is defined as the phenomenon of superimposition of two or more waves of same frequency emitted by coherent sourcessuch that the resultant wave is equal to the sum of the amplitude of the individual waves.
What is ionization interference and how it can be over come?
Ionization interference is a phenomenon which shows a change in emission intensity, causing the ioniza- tion equilibrium to shift, when coexisting elements include easily ionizable elements such as Na, K, Rb, and Cs. Generally, this results in greater intensity of neutral lines and reduced intensity of ionic lines.
What are the types of interferences in atomic absorption spectroscopy?
SPECTRAL INTERFERENCES ๏ข Spectral interferences are caused by presence of another atomic absorption line or a molecular absorbance band close to the spectral line of element of interest. ๏ข Most of these interferences are due to molecular emission from oxides of other element is a sample.
How do releasing agents remove chemical interferences?
Releasing agent. Some chemicals generate chemical interferences in atomic absorption spectroscopy. To remove these interferences, releasing agents are used. These are cations that preferentially react with interferents and prevent chemical interferences via interactions with the analyte.
What are spectral interferences?
Spectral interferences are characterized by an overlap (either partial or direct) of the analyte of interest by an interfering element. Also the background signal for determination of an analyte signal can be interfered.
What are the chemical interferences encountered in the analysis of calcium by atomic absorption spectroscopy?
Only in the case of calcium and strontium determinations were large interferences encountered. The magnitude of the interference was greatest with tungstate and phosphate, and least with fluoride.
What is matrix interference?
Matrix interference means either a positive or negative effect when measuring the concentration of a substance in a sample that creates erroneous results for an analyte.
What are the two main techniques used in analytical chemistry?
The two main methods used are wet chemistry and instrument methods. Wet chemistry, which is the classical approach to analytical chemistry, has been used for centuries. The instrument method is a fairly recent development. Both methods are still used today, but the instrument method is gaining popularity.
How do you solve analytical chemistry problems?
What are the applications of interference?
In optical testing, interference is used in testing surface quality like: flat surface, spherical surface, roughness of surface etc. Whereas in space applications include Radio astronomy, measuring light intensity, in retrieving images from the telescopes.
What are the 3 main objectives of analytical chemistry?
1. to develop an understanding of the range and uses of analytical methods in chemistry. 3. to develop an understanding of the broad role of the chemist in measurement and problem solving for analytical tasks. 4. to provide an understanding of chemical methods employed for elemental and compound analysis.
What Does interference mean on a drug test?
Abstract. Interferences relating to laboratory toxicology testing refer to results which differ from their true value and are often encountered in the setting of a drug screen compared with confirmatory testing.