Automated analysis 112070804013


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Automated analysis 112070804013

  1. 1. Automated analysis Prepared by: Guided by: PARTH PATEL Mr Rajesh Parmar M.Pharm (Q.A.)1
  2. 2. CONTENT…  Introduction  Need for automation  Objective of automation  Advantages automatic analyses  Unit operations in chemical analysis  Types of automated analysis  Flow-injection analysis  Discrete automatic systems  Reference2
  3. 3. INTRODUCTION … Automation is the performance of operations without human intervention. Automation may involve operation like the preparation of samples, the measurements of responses, and the calculation of results.3
  4. 4. NEED FOR AUTOMATION… The partial or complete replacement of human participation in laboratory process. Increasingly stricter control of growing number of samples in which a large number of analytes are to be determined at increasingly low concentration. Cost reduction.4
  5. 5. OBJECTIVE OF AUTOMATION…  Automation is used for : Facilitating an analytical method or technique Processing of large number samples Determination of several components in the same sample Reduction of human participation To avoid error Process ( industrial or otherwise ) control Lowering consumption of sample and/or reagents5
  6. 6. Analytes , which are sometimes present in very low concentration in sample Reagents , some of which are rare or expensive, even unstable Rapidity Economy , in personnel and material expenditure Precision, closely related to the elimination of both definite and indefinite errors arising from human factors Data generation6
  7. 7. ADVANTAGES OF AUTOMATIC ANALYSES… Automated instruments offer a major economic advantage because of their savings in labor costs. Their speed, which is frequently significantly greater than that of manual devices. So, the number of determination per day can be much higher than with manual methods. A well-designed analyzer can usually produce more reproducible results over a long period of time than can an operator employing a manual instrument. The ability to process samples in situation that7 would be dangerous for humans.
  8. 8. UNIT OPERATIONS IN CHEMICALANALYSIS... All analytical methods can be broken down into a series of eight steps, or unit operations, any one of or more can be automated. The next table lists the steps in the order in which they occur in a typical analysis.8
  9. 9. TYPES OF AUTOMATED ANALYSIS…  Automatic analytical systems are of two general types: 1) Discrete analyzers 2) Continuous-flow analyzers9
  10. 10. 1) Discrete analyzers… In this , individual samples are maintained as separate entities and kept in separate vessels throughout each unit operation. The system has many moving parts. Ex. Discrete automatic analyzer  Advantage: Cross contamination among samples is totally eliminated. Inexpensive and reliable10
  11. 11. 2) Continuous-flow analyzers.. In this , the sample becomes a part of a flowing stream where several of the steps take place. Ex. Flow injection analysis Here, interaction among samples are always concern. So, special precaution are required to minimize sample contamination.11
  12. 12. FLOW-INJECTION ANALYSIS... Flow-injection methods are an outgrowth of segmented-flow procedures, which were widely used in clinical laboratories in the 1960s and 1970s for automatic routine determination of a variety of species in blood and urine samples for medical diagnostic purposes. In segmented-flow system , samples were carried through the system to a detector by flowing aqueous solution.12
  13. 13. Instrumentation... In this, a peristaltic pump moves colorimetric reagent directly into a valve that permits injection of samples into the flowing stream. The sample and reagent then pass through a 50 cm reactor coil where the reagent diffuses into the sample plug and produces a colored product by sequence of reactions. From the reactor coil, the solution passes into a flow- through photometer and the signal output from this13 system for a series of standards .
  14. 14. Sample and reagent transport system... Ordinarily, the solution in a flow-injection analysis is moved through the system by a peristaltic pump, a device in which a fluid (liquid or gas) is squeezed through plastic tubing by rollers.14
  15. 15. Sample injectors and detectors... The injectors and detectors employed in flow- injection analysis are similar in kind and performance requirements to those used in HPLC. Sample size for flow injection procedure ranges from 1μL to 200 μL.  For successful analysis, injectors must not disturb the flow of the carrier system. The most common detectors in flow injection are spectrophotometer, photometer and fluorometer.15
  16. 16. Separations in FIA... Separations by dialysis, by liquid/liquid extraction, and by gaseous diffusion are readily carried out automatically with flow-injection systems. 1. Dialysis and gas diffusion 2. Extraction16
  17. 17. 1) Dialysis and gas diffusion... Dialysis is often used in continuous-flow methods to separate inorganic ions, such as chloride or sodium or small organic molecules, such as glucose, from high-molecular-weight species such as proteins. It is used for determination of ions and small molecules in whole blood stream or serum. Gas diffusion from a donor stream containing a gaseous analyte to an acceptor stream containing reagent that permits its determination.17
  18. 18. 2)Extraction... Another common separation technique readily adapted to continuous-flow methods is extraction. Ex. A system for the colorimetric determination of an inorganic cation by extracting an aqueous solution of the sample with chloroform containing a complexing agent such as 8-hydroxyquinoline.  It is important to reiterate that none of the separation procedures in FIA methods are complete.18
  19. 19. analysis... After injection with a sampling valve, it moves through tubing, so band broadening or dispersion takes place. In this, convection arising from laminar flow and creating a parabolic front and skewed zone profile. Diffusion also causes band broadening. Two types of diffusion occur: radial (perpendicular the flow direction) and longitudinal(parallel to the flow direction). At low flow rate, radial diffusion is the major source of dispersion. So, dispersion by both convection and radial19 diffusion occur.
  20. 20. Dispersion... Dispersion D is defined by the equation D = co/c where , co = analyte concentration of the injected sample and c = peak concentration at the detector. Dispersion is influenced by three interrelated and controllable variables: sample volume, tube length, and pumping rate.20
  21. 21. Applications of flow-injection analysis… In the flow-injection literature, the terms limited dispersion, medium dispersion, and large dispersion are frequently encountered where they refer to dispersions of 1 to 3, 3 to 10, and greater than 10, respectively.21
  22. 22. 1) Limited-dispersion applications: Limited-dispersion flow-injection techniques have found considerable application for high-speed feeding of such detector systems as flame atomic absorption and emission as well as inductively coupled plasma . 2)stopped flow methods: It is used for kinetic measurement. 3)flow injection titration: Titration can also be performed continuously in a flow injection apparatus.22
  23. 23. DISCRETE AUTOMATIC SYSTEMS... A wide variety of discrete automatic systems are offered by numerous instrument manufacturers. Some of these devices are designed to perform one or more unit operation. For ex. Determination of nitrogen in organic compounds or determination of glucose in blood.23
  24. 24. Automatic sampling and sampledefinition of liquids and gases... This device consists of a movable probe, which is a syringe needle or a piece of fine plastic tubing supported by an arm that periodically lifts the tip of the needle or tube form the sample container and positions it over a second container in which the analysis is performed.24
  25. 25. Robotics... The robotic system is controlled by a microprocessor that can be instructed to bring samples to the master laboratory station where they can be diluted, filtered, partitioned, ground, centrifuged, extracted, and treated with reagents. For general purpose laboratory robots, robotics units are designed for specific tasks such as loading and unloading of microtiter.25
  26. 26. REFERENCE Skoog D.A. , “Instrumental Analysis” , second edition, New Delhi, 1015 Gary D. Christian, “Analytical Chemistry”, 6th edn, page no 660. Hobart H. Willard, Lynne L. Merrit, “Instrumental Methods of Analysis”, 7th edn, page no- 786. N. Gray, M. Calvin, S C Bhatia, “Instrumental Methods of Analysis”, page no-2726
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