Suppose you are working at your local sewage treatment facility. One of your responsibilities is to monitor the effluent’s biological oxygen demand (BOD), which is a measure of the amount of biologically […]
One method for determining the concentration of glucose in fruit juices is to take advantage of its enzymatic oxidation in the presence of glucose oxidase: β-D-glucose + O2 + H2O → δ-D-gluconolactone […]
Shown below is a plot of initial rate vs. substrate concentration for an enzyme-substrate reaction that follows Michaelis-Menton kinetics. An analyst developing a quantitative method for the substrate wishes to use a […]
The graph shown below is a plot of retention time vs. pH for the reverse-phase HPLC separation of a mixture containing phenacetin, salicylic acid, nicotine, methylamphetamine, and phenobarbituic acid. Based on the […]
In ion-exchange chromatography, a solution containing a mixture of compounds is passed through a column packed with a resin containing covalently attached anionic and/or cationic functional groups. One use of ion-exchange chromatography […]
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 […]
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 […]
The spectrophotometric methods for analyzing Mn and for analyzing glucose use a chemical reaction to produce a useful signal. In the analysis for Mn in steel, colorless Mn2+ is oxidized to give the […]
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) […]
Shown below is a potentiometric titration curve for a 0.050-g sample of an amino acid dissolved in water and titrated with 0.100 M NaOH. Based on this titration curve, answer the following […]
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 […]
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 […]
