Kinetic Method for Manganese
Trace levels of manganese can be determined by measuring its catalytic effect on the oxidation of diethylamine by sodium periodate. The rate of formation of the oxidation product is followed spectrophotometrically. A […]
Calculation
Analysis of Anaerobic Sediments for Sulfides
A paper in the Journal of Chemical Education describes an experimental method for determining the concentrations of both insoluble metal sulfides, such as FeS2, and gaseous H2S in anaerobic sediments. Samples of […]
Neocuproine Method: Analysis of Procedure
One method for determining copper is the “Neocuproine Method”. In this method, copper in a +1 oxidation state reacts with neocuproine (2,9-dimethyl-1,10-phenanthroline) to form a complex of Cu(neocuproine)2. The complex is extracted […]
Standards for the Spectrophotometric Analysis of Acetone
Suppose you need to prepare a set of calibration standards for the spectrophotometric analysis of acetone at a wavelength of 211 nm using a 1.00 cm cell. The molar absorptivity for acetone […]
Titrimetic Analysis of Mixtures
Shown below is a titration curve for a mixture of two monoprotic weak acids, HA and HB, where pKa,HA = 4.00 and pKa,HB = 8.00. The titrant is 0.200 M NaOH. (a) […]
Sampling Plan for Cadmium Leeching from Strip Mine
One of the hazards of strip mining is that water passing through the mine’s “tailings” (the piles of discarded material) is often very acidic and contains high concentrations of metal ions, such […]
Extraction and Analysis of Gingko Leaves
You may know that there is a growing interest in the ginkgo tree because herbal supplements using extracts of ginkgo are believed to aid in fighting memory loss. A recent paper [Lang, […]
Developing a Sampling Plan for Lead in Soil
When leaded gasoline was available, automobiles were a significant source of the total yearly environmental emission of Pb. During internal combustion lead in gasoline, which was present as tetraethyl lead, was vaporized. […]
Separating a Weakly Acidic Analyte from a Weakly Basic Interferent
Imagine you have an aqueous sample containing a weak acid analyte, HA, and a weak base interferent, HI. The following information about HA, HI, the method of analysis, and the sample are […]
Sampling M & Ms
Carry out the following “experiment” to test the validity of the sampling constant equation mR2 = Ks where m is the sample’s mass, R is the relative standard deviation for sampling, and […]
External Standardization for Copper
To determine the concentration of Cu2+ in a sample of water obtained from a local pond, the following solutions were prepared: Solution I: 5.00 mL of sample diluted to 10 mL in […]
Analysis of Pb in Biological and Environmental Samples
A paper by Yan, et. al. [Yan, X.-P.; Sperling, M.; Welz, B. Anal. Chem. 1999, 71, 4216-4222] describes a newly developed analytical method for the analysis of biological and environmental samples containing […]