Standard Calibration Flashcards
Method of identifying a chemical species
Qualitative Analysis
Method to determine the amount of a constituent.
Quantitative Analysis
Quantitative methods can be classified as gravimetric, volumetric, or instrumental.
Used for samples with masses > 0.1 g.
Macro Analysis
Used for samples with masses of 0.01 to 0.1 g.
Semimicro Analysis
Used for samples with masses of 10^-4 to 10^-2 g.
Micro Analysis
used for samples with masses of < 10^-4
Ultramicro Analysis
Present in the range of 1 to 100% by mass.
Major constituents
Present in the range of 0.01 to 1% by mass.
Minor constituents
Present in the range of 100 ppm (0.01%) and 1 ppb.
Trace constituents
Present in amounts lower than 1 ppb.
Ultratrace constituents
Occur when extraneous species in the matrix interfere with determination of the analyte.
Matrix effects
Samples are analyzed, but constituents or concentrations are determined.
Acquiring a representative fraction of the material of interest. It is often the most difficult aspect of an analysis.
Sampling
Items chosen for analysis.
Sampling units or sampling increments
The collecting of sampling units or increments. A miniature replica of the entire mass of material to be analyzed
Gross sample
The gross sample is usually reduced in size and homogenized to create the laboratory sample for analysis.
Two goals of the sampling process.
To obtain a mean analyte concentration that is an unbiased estimate of the population mean.
To obtain a variance in the measured analyte concentration that is an unbiased estimate of population variance.
A state intermediate between a suspension and a solution.
Colloid
Mimics the steps in a determination that would be taken by a human analyst.
Batch or discrete approach
Involve inserting the sample into a flowing stream where several operations can be performed before the sample passes through a flow-through detector.
Continuous flow methods
Divide a sample into discrete samples separated by gas bubbles that confine the sample and minimize cross-contamination.
Segmented-flow analyzers
A band-spreading or mixing phenomenon that results from the coupling of fluid flow with molecular diffusion.
Dispersion
Mass transport due to a concentration gradient.
Diffusion
Mass transport due to a concentration gradient.
Diffusion
A\continuous flow approach in which samples are injected into a flowing stream containing one or more reagents.
Flow injection analysis (FIA)
Determines the relationship between the analytical response and the analyte concentration.
Calibration
Usually used to determine this relationship.
Chemical Standards
Constituents of the sample other than the analyte.
Concomitants
Concomitants that interfere with the determination of the analyte.
Interferents or interference
Procedures that involve comparing a property of the analyte or the product of a reaction with the analyte with standards to determine if the property matches or nearly matches the standard.
Null comparison or isomation methods
Determine whether an analyte concentration exceeds or is less than a threshold level.
Comparator
In titration, the analyte reacts with a standardized reagent (the titrant) in a known stoichiometric manner until the titration reaction is complete.
In external standard calibration, a series of standard solutions is prepared and used to establish the instrument calibration function from analysis of the instrument response as a function of the known analyte concentrations.
A plot of instrument response versus known analyte concentrations is used to produce a calibration curve (also called a working curve).
Provides a means to objectively determine the best fit line to data points, such as those in a calibration curve, and for specifying the uncertainties associated with its subsequent use.
Regression analysis
The vertical deviation of each point from the straight line.
Residual
The standard deviation about regression, standard error of the estimate, and standard error are all terms for the same value, which is a rough measure of the magnitude of a typical deviation from the regression line
Used to correct a raw analytical response.
Blank
Identical to the solvent but without the analyte but is often too difficult or impossible to prepare.
Ideal Blank
Real blanks are either solvent blanks, which contain the same solvent as the sample, or reagent blanks that contain the solvent plus all the reagents used in sample preparation.
Involves adding the interfering species to all the samples, standards, and blanks so that the interference effect becomes independent of the original concentration of the interfering species in the sample.
Saturation method
A species that is added to samples, standards, and blanks in sufficient amounts to make the analytical response independent of the concentration of the interfering species.
Matrix modifier
Reacts selectively with interfering species to form a complex that does not interfere.
Masking agent
Attempts to duplicate the sample matrix by adding the major matrix constituents to the standard and blank solutions.
Matrix-matching method
A reference species, chemically and physically similar to the analyte that is added to samples, standards, and blanks.
Internal Standard
A known amount of a reference species is added to all the samples, standards, and blanks and the measurement response is the ratio of the analyte response to the reference species response.
Single-point addition
Additions of known amounts of standard analyte solution are made to several portions of the sample, and a multiple additions calibration curve is obtained.
Multiple addition
It is a numerical expression representing the performance or efficiency of a given device, material, method, or procedure.
Figure of merit
The change in the measured quantity per unit change in analyte concentration. This is the slope of the calibration curve.
Calibration sensitivity
Scatter in the response
Noise
The ratio of calibration curve slope to the standard deviation of the analytical signal at a given analyte concentration.
Analytical Sensitivity
The smallest concentration that can be reported with a given level of confidence.
Detection limit, DL
Refers to the concentration range over which the analyte can be determined using a linear calibration curve.
Linear dynamic range
A sequential plot of some quality characteristic that is important in quality assurance.
Control Chart
If the mean value remains between the LCL and the UCL, an instrument is in statistical control.
Transformations do not give good estimates if the errors are not normally distributed.
