1 INTRODUCTION The purpose of LABORATORY is

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INTRODUCTION The purpose of LABORATORY is to assist in QUALITY CONTROL of the Raw Material, intermediates and products in a manufacturing unit: 2

Following samples are tested in FFBL Laboratory: ØRaw materials (Natural Gas, Phos Acid, Liquid Ammonia, Water etc. ) ØDifferent Samples from Ammonia, DAP, Urea and Utilities plants at different stages of processing. ØPackaging materials. ØEnvironmental Control Analysis. ØSpecial samples like metals & Alloys, scales & Deposits, Lube Oils, Plant Chemicals e. g. Potassium Carbonate, Tri Sodium Phosphate, Hydrazine, H 2 SO 4, Na. OH Solution etc. ) Above samples may be in solid, liquid, or gaseous form. Different analytical methods are used for these analysis. 3

Methods of analysis Quantitative methods of chemical analysis can be categorized into following types: 1. Classical (or wet) methods include: Titrimetric, Gravimetric and Volumetric analysis 1. Instrumental methods Chromatography, spectroscopy , electrochemistry, Karl fisher titration, potentiometry, ion selective analysis. 4

Advantages of instrumental analysis over classical methods ØAccuracy: Because of repeatable results and fine calibration we can achieve more accurate results. For example: Automatic p. H titrator is more accurate than manual indicator titration. ØPrecision: Results obtained from instruments are more precise than manual system. With the help of instruments we can achieve analysis results upto PPB level. ØTime saving: Automatic analyzers can perform hundreds of samples by using automated samplers. Thus saving many man-hours. 5

DIFFERENT TYPES OF INSTRUMENTS BEING USED IN OUR LABORATORY: ØGAS CHROMATOGRAPH ØATOMIC ABSORPTION SPECTROPHOTOMETER ØUV-VISIBLE SPECTROPHOTOMETER ØKARL FISHER TITRATOR Ø AUTOMATED KJELDHAL DIGESTOR AND DISTILLATOR ØCONDUCTIVITY METER Øp. H METER 6

Gas Chromatograph (GC) This instrument is used to analyze various gas samples from Ammonia, Urea and Utilities plants. 7

Principles of Gas Chromatography: This method is based on adsorption of gaseous substances on solid surfaces in presence of gaseous mobile phase. This results in separation of the mixture of gases into individual components. Degree of separation depends on molecular weight, boiling point and affinity of adhesion with the solid phase. Permanent gases (N 2, Ar, CO & CO 2) and components of Natural gas (Hydrocarbons) are separated analyzed. 8

Gas Chromatograph H RESET Gas Carrier Hydrogen Air ØGas inlet system ØColumn ØDetector ØData system 9

Schematic Diagram of Gas Chromatograph 10

Commonly Used Detectors for GC: ØThermal conductivity (TCD): Change in resistance of heated wire based on variation in thermal conductivity of the gases evolving from the column (wheat stone bridge principle) ØFlame ionization (FID): Destruction of combustible sample results in production of ions in flame produces measurable current. 11

AA Spectrophotometer Atomic Absorption spectrophotometer is being used in our laboratory for various metal & non-metal analysis. 12

BASIC PRINCIPLES: ATOMIC ABSORPTION SPECTROSCOPY (AAS) is an analytical technique that uses absorption of light by the atoms of elements in order to measure their concentration. ATOMIC EMISSION SPECTROSCOPY is also an analytical technique that uses emission of light from excited atoms to determine analyte concentration 13

Schematic Diagram of an Atomic Absorption Spectrometer Light source atomizer hollow cathode Lamp monochromator Detector and readout device 14

Atomic absorption spectrometers have 4 major components 1 - A light source ( usually a hollow cathode lamp ) 2 - An atomizer 3 - A monochromator 4 - A detector , and read out device. 1 - Light Source: The light source is usually a hollow cathode lamp of the element that is being measured. It contains a tungsten anode and a hollow cylindrical cathode made of the element to be determined. 15

Hollow Cathode Lamp Quartz window Anode Cathode Pyrex body Cathode Anode 16

2 – Atomizer: Elements to be analyzed need to be in atomic state. Atomization is conversion of particles into individual molecules and breaking molecules into atoms. This is done by exposing the analyte to high temperatures in a flame or a flameless graphite furnace. 17

Flame: Flame AA can only analyze solutions , where it uses a slot type burner to increase the path length, resulting in increase in the total absorbance. Sample solutions are usually introduced into a nebuliser by a capillary tube. In the nebuliser the sample is dispersed into tiny droplets , which can be readily broken down in the flame to atoms. Air / Acetylene and N 2 O / Acetylene type flames are generally used depending on nature of analyte. 18

Sample Introduction System Nebuliser Capillary Solution 19

4 - Detector and Read out Device The light selected by the monochromator is directed on to a detector that is typically a photomultiplier tube , whose function is to convert the light signal into an electrical signal. 20

UV Spectrophotometer 21

PRINCIPLE OF UV/VIS SPECTROPHOTOMETER: When a monochromatic light is passed through a solution of any colour, it is absorbed Somewhat the magnitude of absorption depends on concentration of colour. Lambert-Beer's Law: Solution absorbance α concentration (at a certain limit) 22

Standard Curve, Calibration curve: 23

Different types of spectrophotometer are available depending on according and range. A simple photometer works in visible range. More sophisticated instruments have wide range and better precision. Components of UV/Visible Spectrophotometer: 24

Application: We use spectrophotometer to measure the concentration of different elements and compound in PPM and PPB level like Phosphate, Silica, Vanadium, DEA, Iron, Hydrazine etc. in various samples. 25

Karl Fisher Titration Karl Fisher titration is based on reaction between iodine and sulfur dioxide in an aqueous medium. 26

WORKING: Water and iodine are consumed in a 1: 1 ratio in the above reaction. Once all of the water present is consumed, the presence of excess iodine is detected by double pin platinum electrode. . USES: Karl fisher titrator is used for the determination of water content in urea granules and lube oil samples. It can also be used for other materials like solvents, raw chemicals etc. 27

Conductivity Meter Principle: When two electrodes are immersed in a solution and a potential is applied across them, a current will be produced in the external circuit that connects the two electrodes in the presence of Ions. ØNon. -ionic solutions cannot conduct electricity. ØConductivity is directly proportional to ionic Concentration. ØConductivity measures in mμ/cm 28

p. H Meter p. H meter is used to measure the acidity or alkalinity of aqueous samples p. H meter can also be used as m. V Meter electrometric titrations. It can be used as end point titrator as a substitute of p. H indicator titration. 29

PARTS OF p. H METER: Measuring device To Accurately measures and transforms the voltage into a p. H value Sensing probe Generally called p. H electrode to sense all the H+ ions and to produce a potential. 30

Applications: Demin water, boiler’s water, Condensates , waste water effluents etc. are regularly checked for p. H at our plant to maintain the quality of these waters. Generally combination p. H electrode is used for its simplicity and ease of handling 31

Ion Selective Electrode ISE consist of the ion-selective membrane, an internal reference electrode, an external reference electrode, and a measuring device which is same as a p. H meter. 32

Applications: Ion-selective electrodes are used in a wide variety of applications for determining the concentrations of various ions in aqueous solutions. • Pollution Monitoring: CN, F, S, Cl, NO 3 etc. , in effluents, and natural waters. • In our laboratory we have different ion selective electrode for example • Fluoride ISE for measuring F in phosphoric acid - • Chloride for measuring CL contents in condensates, cooling water, CBD’s etc + • Sodium for measuring Na contents in steam condensates etc. 33

Questions If Any ? 34