Spraying solvent polarity

In an ESI source, the sample M is dissolved in a polar solvent and sprayed through a steel capillary tube. As it exits the tube, it is subjected to a high voltage that causes it to become protonated by removing H+ ions from the solvent. The volatile solvent is then evaporated, giving variably protonated sample... 

Besides the calculation of the different sulfonated species, it is also possible to determine them directly by chromatographic methods. Separation of the ester sulfonate and the disodium salt is achieved by thin-layer chromatography on silica gel plates. With a solvent mixture of acetone and tetrahydrofuran (90 10 v/v) the disodium salt stays at the start whereas the ester sulfonate has an R value of 0.2. With the more polar solvent 0.1 N H2S04 + methanol + chloroform the ester sulfonate and the disalt have Rf values of 0.36 and 0.14. For visualization, the plate is sprayed with pinacryptol yellow. In UV light (254 and... 

Concentrates are made by extracting water-soluble sugars and other compounds from defatted meals or flours. This is typically a secondary extraction, using acidic ethanol-water in a chain-type or basket-type continuous extractor for processing flakes, or acidic water extraction of flour in vats, followed by spray-drying (8). Acidic polar solvents are used at or near the isoelectric point of the protein to minimize its solubility and loss. The reextracted flakes may then be ground into a flour. Concentrates are more bland than defatted flours, but still contain the fiber components of the kernel. After extraction with acidic ethanol or water, concentrates... 

Atmospheric pressure chemical ionization APCI is a method closely related to electrospray ionization. It uses ion-molecule reactions to produce ions from analyte molecules. The sample is electrohydrodynamically sprayed into the source (Figure 14.3). The evaporation of the solvent is often supported by a heated gas at temperatures between 80 and 400°C. Within the source, a plasma is created using a corona discharge needle that is placed close to the end of the metal capillary. In this plasma, proton transfer reactions occur, leading to the ionization of the analyte, mainly by the formation of [M+H]+ ions. Compared to ESI MS, APCI MS is very well suited for the analysis of less-polar components and can therefore... 

PVP is a flexible polymer which is soluble in water and other polar solvents. PVP has a Tt of 17.S C. Solutions of PVP are used in hair spray formulations and as blood extenders. 

El-Deeh, et al (175) have reported the separation and evaluation of camphor by TLC technique on silicic acid plate.The behaviour of camphor on chromatoplates was studied using different solvents of increasing polarity and their mixtures as developers. The spots were located by spraying the plates first with sulphuric acid and then with k0% solution of Formaldehyde and heating the plate to 100°C for 3 to 5 minutes. The Rf values were calculated. It is given in Table 7. 

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