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| exploit differences in physical an chemical properties for analytical analysis |
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| can be represented as a continuous function on a graph |
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| Takes discrete step by step points along the graph |
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| something that detects any change in an environmental variable of interest |
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| device that converts nonelectrical information to electrical signals and vice verca |
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| analytical devices that are capable of monitoring specific chemical species continuously |
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| determines the relationship between analytical response and analyte concentration |
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| the property being tested or nearly matches that of the standard |
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| the amount of titrant needed until chemical equivalence is achieved as a function of analyte concentration. Usually indicated by color change. |
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| A series of external standards prepared with a known concentration of analyte and plotting a calibration curve with response signal as a function of analyte concentation. The unkown analyte concentration can then be determined using y=mx+b |
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| a method where a standard solution is added in varying increments to sample aliquots of identical volumes, then diluted to a fixed volume. In this method, the sample matric is nearly identical with the only difference being analyte concentration. A least squares analysis is used to find m and b and the analyte concentration can be found by cx=(b*cs)/(vx*m) |
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| a method which has a known concentration of substance in every sample with a similar signal to the analyte, but can stil be distinguished from the analyte. In this method, ideally, any factor that affects the analyte also affects the internal standard. Thus, making a ratio of the two exhibit less variability. Plotting a calibration curve of ratio as a function of anaylte concentration allows you to determine the analyte concentration |
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| is a quantity used too to characterize the performance, system or method, relative to alternatives. Includes: precision, bias, signal to noise,detection limit, sensitivity, selectivity, dynamic range |
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| The reproducibility of mesurements |
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| how close measurments come to the true or accepte value |
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| measure of systematic error of a particular analytical method =mean-(true value) |
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| how much individual data points deviate from the mean |
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| Coefficient of variation (CV) |
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| Ability to discriminate between small differences in analytical concentrations. Related to slope of calibration curve (gamma= m/sx) |
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Minimum concentration of analyte that can be detected at a known confidence interval
sm=(Sbl-bar)-k(sbl)
cm=(sm-sbl)/m |
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| Range of an analytical method extending from lowest a conc. at which quatntitation can be made to the conc at which the calibration curve is no longer linear |
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| the degree to which the method is free from interference by another species in the sample matrix |
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| Uncertainties resulting from the operation of small uncontrolled variable that are inevitable and affect the precision of the measurements |
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| errors that have a known source, affect measurements in only one way and can be acounted for |
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| Errors caused by imperfections in measuring devices and imperfections in their componets |
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| errors that arise from non-ideal chemical or physical behavior of an analytical system |
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| Errors that Result from the carelessness, inattention or personal limitation of the experimenter |
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| E= average value - true value |
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| Er = (average value - true value)/true value |
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| Refers to the entire assemblies that indicate or record physical or chemical quantities |
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