Wool sequential

A sequential analysis protocol includes three steps (1) extraction in water or other appropriate solvent for the colorant, (2) purification or concentration of the colorant, and (3) separation coupled with detection of the target molecule. Different methods of extracting synthetic colorants from foods have been developed using organic solvents followed by SPE protocols using as adsorption support RP-C18, amino materials, or Amberlite XAD-2. Eor qualitative evaluations, the easiest option for separating colorant molecules from unwanted ingredients found in an extract is SPE on polyamide or wool. 

The functions of the reagents used in the reduction of arsenic compounds, such as Zn, HCl, NiCla, SnCh, and KI are discussed below in connection with the Gutzeit method. Sodium borohydride also has been proposed as the reducing agent [39-42]. Sequential spectrophotometric determination of As(III) and As(V) is possible by using borohydride [40]. Hydrogen sulphide, which interferes in the reaction, is separated from arsine on cotton wool impregnated with lead acetate. 

Various fibers may be identified, or separated from each other, through sequential dissolution in various solvents. As seen in Figure 6, silk is soluble in HCOOH/ZnCli, while wool does not dissolve. For bast fibers it is possible to discern some types with phloroglucin/HCl under a microscope. Jute will stain red, while hemp is only slight pink, and ramie and flax are unaltered. With the use of Kuoxam, ramie is dissolved while flax remains undissolved. For these tests, it is absolutely necessary to use reference materials ... 

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