Abstract Protein preconcentration is an essential sample preparation step for analysis in which the targeted proteins exist in low concentrations. such as bodily fluids. water. or wastewater. https://www.bekindtopets.com/limited-value-SharkBite-U648LF-Lead-Free-Brass-Push-to-Connect-45-Degree-Elbow-1-2-x-1-2-mega-super/