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T1 Standard procedure for the determination of P in cheese. An interactive lab experiment.
A1 Milla González, Miguel
A2 Química Analítica
K1 quantitative analysis
K1 instrumental methods
K1 spectrophotometry
K1 molybdenum blue
K1 cheese analysis
K1 determination of phosphorus
K1 determination of phosphorus in cheese
K1 mineralization of a cheese sample
K1 standard procedure for P in cheese
K1 interactive chemistry
K1 interactive lab experiment
AB A spectrophotometric method is used for the determination of P content in a sample of cheese. The procedure is based on the formation of molybdenum blue and measurement of the absorbance at 820 nm. The interactive experiment starts with the weighing of the cheese sample in the range 0.2-0.45 g (analytical balance, four significant figures). A random weight of cheese is obtained. Then, according to the procedure, the cheese is mineralized to convert P into phosphate which is treated with the molybdenum reagent to yield molybdenum blue. The absorbance of both samples and standards are measured at 820 nm. A calibration graph is constructed from the data of the P standard solutions and the least squares method is applied to obtain the corresponding equation. Finally, using this equation, the concentration of P (as mass percent) in the cheese is found. All data in the simulated experiment are randomly generated. In the calibration step, an outlier can appear that can be rejected by application of the Dixon’s test. The final result is expressed in terms of the mean value with the associated statistical treatment.
YR 2014
FD 2014-10-27T00:00:00Z
LK http://hdl.handle.net/10498/16749
UL http://hdl.handle.net/10498/16749
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 13-nov-2026