Titrimetric Analysis of Amino Acids
The quantitative titrimetric analysis of amino acids often is complicated by the high pKa of the —NH4+ group, which produces a titration break that is too small for the effective use of […]
Analytical Problem Exchange
Use the problems in this forum to jump-start your in-class exercises, out-of-class assignments, or use them in exams.
Complexometric Titration of CaO in Limestone: Analysis of Procedure
In the EDTA titration for CaO in limestone, the pH of the sample is made sufficiently basic so any magnesium thatis present will precipitate as Mg(OH)2. The adjustment of pH is fairly […]
Gravimetric Method for Analysis of Phosphorous: Analysis of Procedure
Once upon a time, a common method for determining phosphorous was to convert it to phosphate, precipitate it as magnesium ammonium phosphate, MgNH4PO4, and ignite it to form magnesium pyrophosphate, Mg2P2O7. The […]
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 […]
Analysis of a Digital Pipet
Mechanical micropipets are commonly used to dispense small (μL) volumes of reagents. A recent “Application Note” [Am. Lab. June 1999] contains the following data for 50 replicate deliveries of a reagent using […]
Analysis of Basic Copper Carbonates
The %w/w Cu in a synthetic basic copper carbonate may be found by reducing and isolating the copper as Cu metal. To calculate the %w/w Cu we use the following formula The […]