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Blank Value
A blank value in analytical chemistry is a measurement of a blank. The reading does not originate from a sample, but the matrix effects, reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...s and other residues. These contribute to the sample value in the analytical measurement and therefore have to be subtracted. The limit of blank is defined by the Clinical And Laboratory Standards Institute as the highest apparent analyte concentration expected to be found when replicates of a sample containing no analyte are tested. See also * Blank (solution) References Analytical chemistry {{analytical-chem-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Analytical Chemistry
Analytical chemistry studies and uses instruments and methods to separate, identify, and quantify matter. In practice, separation, identification or quantification may constitute the entire analysis or be combined with another method. Separation isolates analytes. Qualitative analysis identifies analytes, while quantitative analysis determines the numerical amount or concentration. Analytical chemistry consists of classical, wet chemical methods and modern, instrumental methods. Classical qualitative methods use separations such as precipitation, extraction, and distillation. Identification may be based on differences in color, odor, melting point, boiling point, solubility, radioactivity or reactivity. Classical quantitative analysis uses mass or volume changes to quantify amount. Instrumental methods may be used to separate samples using chromatography, electrophoresis or field flow fractionation. Then qualitative and quantitative analysis can be performed, often with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blank (solution)
A blank solution is a solution containing little to no analyte An analyte, component (in clinical chemistry), or chemical species is a substance or chemical constituent that is of interest in an analytical procedure. The purest substances are referred to as analytes, such as 24 karat gold, NaCl, water, etc. ... of interest, usually used to calibrate instruments such as a colorimeter. According to the EPA, the "primary purpose of blanks is to trace sources of artificially introduced contamination." Different types of blanks are used to identify the source of contamination in the sample. The types of blanks include equipment blank, field blank, trip blank, method blank, and instrument blank. References Analytical chemistry {{analytical-chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Matrix Effect
In chemical analysis, matrix refers to the components of a sample other than the analyte of interest. The matrix can have a considerable effect on the way the analysis is conducted and the quality of the results are obtained; such effects are called matrix effects.F. W. Fifield, P. J. Haines. ''Environmental Analytical Chemistry''. Blackwell Publishing, 2000, p. 4-5. . For example, the ionic strength of the solution can have an effect on the activity coefficients of the analytes.Harris, D. C. ''Quantitative Chemical Analysis'', 4th ed. Freeman, 1995, pp.194, 404. . The most common approach for accounting for matrix effects is to build a calibration curve using standard samples with known analyte concentration and which try to approximate the matrix of the sample as much as possible. This is especially important for solid samples where there is a strong matrix influence.Marco Aurelio Zezzi Arruda. ''Trends in Sample Preparation''. Nova Publishers, 2006, p. 15-18. . In cases with comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reagent
In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a substance ''consumed'' in the course of a chemical reaction. ''Solvents'', though involved in the reaction mechanism, are usually not called reactants. Similarly, ''catalysts'' are not consumed by the reaction, so they are not reactants. In biochemistry, especially in connection with enzyme-catalyzed reactions, the reactants are commonly called substrates. Definitions Organic chemistry In organic chemistry, the term "reagent" denotes a chemical ingredient (a compound or mixture, typically of inorganic or small organic molecules) introduced to cause the desired transformation of an organic substance. Examples include the Collins reagent, Fenton's reagent, and Grignard reagents. Analytical chemistry In analytical chemistry, a reagent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Residue (chemistry)
In chemistry, residue is whatever remains or acts as a contaminant after a given class of events. Residue may be the material remaining after a process of preparation, separation, or purification, such as distillation, evaporation, or filtration. It may also denote the undesired by-products of a chemical reaction. Food safety Toxic chemical residues, wastes or contamination from other processes, are a concern in food safety. For example, the U.S. Food and Drug Administration (FDA) and the Canadian Food Inspection Agency (CFIA) have guidelines for detecting chemical residues that are possibly dangerous to consume. Characteristic units within a molecule ''Residue'' may refer to an atom or a group of atoms that forms part of a molecule, such as a methyl group. Biochemistry In biochemistry and molecular biology, a residue refers to a specific monomer within the polymeric chain of a polysaccharide, protein or nucleic acid. One might say, "This protein consists of 118 amin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blank (solution)
A blank solution is a solution containing little to no analyte An analyte, component (in clinical chemistry), or chemical species is a substance or chemical constituent that is of interest in an analytical procedure. The purest substances are referred to as analytes, such as 24 karat gold, NaCl, water, etc. ... of interest, usually used to calibrate instruments such as a colorimeter. According to the EPA, the "primary purpose of blanks is to trace sources of artificially introduced contamination." Different types of blanks are used to identify the source of contamination in the sample. The types of blanks include equipment blank, field blank, trip blank, method blank, and instrument blank. References Analytical chemistry {{analytical-chemistry-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
