ANACHEM

• Separation techniques are those techniques that can be used to separate two different states of matter such as liquids and solids.
• Separation processes or a separation method or simply a separation is methodology to attain any mass transfer phenomenon that convert a mixture of substances into two or more distinct product mixtures
• Separation is an important asset to purify component of interest from a mixtures.
• NEED OF SEPARATION TECHNIQUES: • TO IDENTIFY WHAT TO BE SEPARATED FROM MIXTURE. • TO OBTAIN IMPORTANT AND PURE SUBSTANCES. • TO REMOVE UNWANTED PARTICLES.
• For solid in liquid mixtures • Homogenous: — Evaporation — Distillation — centrifugation • Heterogenous: — Sedimentation / gravitation — Filtration — Magnetic separation — Fractional distillation
• Magnetic Separation • This method involves the separation of magnetic substances from non-magnetic substances by means of magnet
• For liquid in liquid mixtures • Homogenous: — Simple or fractional distillation. — Chromatography • Heterogenous: — Partition separation using funnel
• Takes advantage of physical property of magnetism, so it useful only for certain substances such as ferromagnetic (materials strongly affected by magnetic fields) and paramagnetic (materials that are less affected, but the effect is still noticeable).
• DECANTATION - is a process for the separation of mixtures of immiscible liquids or of a liquid and a solid mixture such as a suspension.
• A separatory funnel - is an alternative apparatus for separating liquid layers. • It has a valve at the bottom to allow draining off the bottom layer. • It can give a better separation between the two liquids.
• Sedimentation: The tendency of particles in suspension to settle down in the fluid due to certain forces like gravity, centrifugal acceleration, or electromagnetism is called as sedimentation. • The solid that gets settled down is called as sediment.
• A decanter centrifuge may be used for continuous solid liquid separation.
• a Büchner funnel is often used, with a filter paper serving as the porous barrier
• Decantation is frequently used to purify a liquid by separating it from a suspension of insoluble particles.
• Fat is determined in butter by decantation
• FILTRATION: • Takes advantage of physical property of state of matter, its size and solubility in liquid. • Mechanical, physical or biological operations that separates solids from fluids (liquids or gases) by a medium through which only the fluid can pass can be called as filtration. • The substance which is left behind in the filtration medium is called residue. • The liquid which passes through the filtration medium is called filtrate
• CENTRIFUGATION: • It is used to separate mixtures where the solid particles don't settle faster and which are of very small size and can't be separated by filtration. • Centrifugation is a technique which involves the application centrifugal force to separate particles from a solution according to their size, shape, density, viscosity of the medium and rotor speed. • A centrifuge is a device that separates particles from a solution through use of a
• EVAPORATION: • Evaporation is type of vaporization that occurs on the surface of liquid as it changes into gas phase. • This separation technique can be used to separate solutes that are dissolved in solvent, by boiling the solution. The solvent gets vaporized leaving back the solute.
• DISTILLATION: • is an effective method to separate mixtures comprised of two or more pure liquids (called "components"). • The separation of a mixture of liquids based on the physical property of boiling point. • is a purification process where the components of a liquid mixture are vaporized and then condensed and isolated. • The mixture is heated until one of the components boils (turns to a vapor)
• The vapor is then fed into a condenser, which cools the vapor and changes it back into a liquid that is called distillate. What remains in the original container is called the "residue".
• Simple: Used to separate liquid mixtures which boil without decomposition and have enough difference in their boiling points
• Fractional: is used for the separation of a mixture of two or more miscible liquids for which the difference in boiling points is less than 25K
• Crystallization is the (natural or artificial) process by which a solid forms, where the atoms or molecules are highly organized into a structure known as a crystal.
• Sublimation is the transition of a substance directly from the solid to the gas phase, without passing through the intermediate liquid phase.
• This technique takes the advantage of substance's sublimable property.
• Chromatography is a separation technique used to separate the different components in a liquid mixture
• The mixture is dissolved in a fluid called the mobile phase, which carries it through a structure holding another material called the stationary phase
• EXTRACTION TECHNIQUES:

  • Involves the separation of medicinally active portions of plant or animal tissues from the inactive or inert components by using selective solvents in standard extraction procedures
• Liquid Chromatography -testing water samples to look for pollution-Used to analyze metal ions and organic compounds in solutions. It uses liquids which may incorporate hydrophilic, insoluble molecules.
• Gas Chromatography -detecting bombs in airports, identifying and quantifying such drugs as alcohol, being used in forensics to compare fibres found on a victim-Used to analyze volatile gases. Helium is used to move the gaseous mixture through a column of absorbent matenal.
• Thin-Layer Chromatography -detecting pesticide or insecticide residues in food, also used in forensics to analyze the dye composition of fibres-Uses an absorbent material on flat glass plates. This is a simple and rapid method to check the purity of the organic compound.
• Paper Chromatography -separating amino acids and anions, RNA fingerprinting, separating and testing histamines, antibiotics-The most common type of chromatography. The paper is the stationary phase. This uses capillary action to pull the solutes up through the paper and separate the solutes.
• Steps Involved In Analysis

  1. Preparation of the solution.

  2. Precipitation

  3. Digestion.

  4. Filtration.

  5. Washing.

  6. Drying / Ignition.

  7. Weighing.

  8. Calculation.
• Gravimetric Analysis is a group of analytical methods in which the amount of analyte is determined by the measurement of the mass of a pure substance containing the analyte. It is and ABSOLUTE method.
• There are two main types of gravimetric analysis:

  • Precipitation

  • Volatilization
• Advantages -

  — Accurate and precise.

  — Possible sources of errors can be checked.

  • Disadvantages: -

  — Proper lab technique is critical.

  — Time consuming.

  — Coprecipitation is a major drawback.