Messung ohne Eichkurven

Čupr, V.; Pelikan, Juraj

doi:10.1007/bf00459301

Cited by 2 publications

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“…It is frequently used in trace analysis, where additions represent "spikes" of known concentration, or where analyte samples with a complicated matrix are available [8][9][10][11]. It is frequently used in trace analysis, where additions represent "spikes" of known concentration, or where analyte samples with a complicated matrix are available [8][9][10][11].…”

Section: ^X+s ^Xmentioning

confidence: 99%

Evaluation of the Analyte Concentration from Spectrophotometric Data

1989

Studies in Analytical Chemistry

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The determination of an unknown analyte concentration is carried out with the aid of a particular spectrophotometric procedure under optimized conditions, and a suitable treatment of the absorbance data at selected wavelengths. It is assumed that the BLB law is obeyed and that the measurements are of sufficient precision and accuracy. Appropriate calibration plots are prepared by use of standard solutions. Optimum working concentration interval of the analyteThe optimum concentration interval of the analyte corresponds to the strictly linear part of the plot of absorbance vs. analyte concentration for which the BLB law is strictly obeyed and the measurement precision is acceptable. Since the error of absorbance readings rapidly increases for Λ>1.8, at least using common spectrophotometers, the most suitable analyte working interval is related to the range A = 0.050-1.80. This is in spite of the fact that a value A = 3.000 can also be read within a reproducibility of _ 0.006 A if a highly precise double-beam and double-pass instrument providing digital display is used. Absorbance intervals such as 0.1 < Λ > 1.2 [1], A = 0.1-1.2 [15] or v4 =0.1-1.1 but also 0.1-1.8 [2] were previously recommended when single-beam or classical double-beam-in-space photoelectric or visual instruments were used with optical, mechanical or electrical beam attenuators. Preparation of calibration plots and their treatmentThese are prepared from a sufficient number of standard solutions or aliquots of different concentrations under optimum conditions usually with a 10-mm cell path length. There are various types of calibration plots, e.g., A vs. COT (A -v4 blank ) vs. c. The number of standard aliquots or replicate solutions used for the plotting depends on the purposes for which the spectrophotometric procedure is employed and the kind of statistical treatment of the absorbance data: 7 Analytical 7*

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