title: Autoanalyzer for milk quality control based on the lactose, fat, and total protein contents.
abstract: A novel autoanalyzer was developed to assess the quality of milk samples according to the percentage of lactose, fat, and total protein they contain. The module comprises two pumps (one of high pressure), an injection valve, a filter, and an evaporative light-scattering detector. A volume of 15 microL of dilute milk was injected in an ethanol-water (50% v/v) stream for precipitation/retention of protein/fat, being the lactose content determined in the filtrate. The fat fraction was calculated using an ethanol stream, and total protein was finally dissolved by means of a 1.7 mol/L acetic acid solution. The simplicity of the proposed automatic module lies in the universal response of the detector, which permits the determination of the three macrocomponents in milk. In addition, the flow injection method allows their sequential analysis in the same injected sample by using selective reagents for each compound. The proposed method was validated with an SRM milk sample as well as by comparison of the results obtained with those provided by the IR method. In addition, the proposed analyzer is cheaper than its counterpart that is based on infrared technique.
authors.affiliation: Department of Analytical Chemistry, Campus de Rabanales, University of Córdoba, E-14071 Córdoba, Spain.
authors.forename: Rafael
authors.initials: R
authors.lastname: Lucena
authors.forename: Mercedes
authors.initials: M
authors.lastname: Gallego
authors.forename: Soledad
authors.initials: S
authors.lastname: Cárdenas
authors.forename: Miguel
authors.initials: M
authors.lastname: Valcárcel
mesh_terms: D000818:Animals; D001331:Automation; D004867:Equipment Design; D005223:Fats / Q000032:analysis; D007785:Lactose / Q000032:analysis; D008722:Methods; D008892:Milk / Q000737:chemistry* / Q000592:standards*; D009391:Nephelometry and Turbidimetry / Q000379:methods; D011506:Proteins / Q000032:analysis; D011786:Quality Control; D012542:Scattering, Radiation
chemical_list: D005223:Fats; D011506:Proteins; D007785:Lactose