Abstract
Quality affinity isolation experiments are necessary to identify valid protein-protein
interactions. Biological error, processing error, and random variability can reduce
the quality of an experiment, and thus hinder the identification of protein interaction
pairs. Appraising a�nity isolation assay quality is essential to inferring protein
associations. An important step of the assay is the mass spectrometric identification
of proteins. To evaluate this step, a known mixture of proteins is processed through
a mass spectrometer as a quality control mixture. If the mass spectrometer yields
unexpected results, the process is currently qualitatively evaluated, tuned, and reset.
Statistical quality control (SQC) procedures, including the use of cumulative sum,
the individual measurement, and moving range charts are implemented to analyze
the stability of the mass spectrometric analysis. The SQC measures presented here
can assist in establishing preliminary control limits to identify an out-of-control
process and investigate assignable causes for shifts in the process mean in real-time.