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teknik biokimia

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teknik biokimia

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  1. ACCURACY AND PRECISION Sukarti Moeljopawiro Laboratorium BiokimiaFakultas Biologi

  2. Accuracy and Precision • Accuracy: May be defined as the degree of conformity to the truth • Precision: • The degree of agreement between replicate experiments • Precision does not mean accuracy, since measurements may be highly precise but inaccurate due to a faulty instrument

  3. Type of errors • Errors may be: • Random • Careless • Inaccurate instruments • Random error which are individually unpredictable • Errors can arise from careless experiments work: • Using apparatus wrongly • Do not read the manufacture’s instructions • Using broken instruments

  4. Standard and blank • To obtain a value as accurate as possible from an estimation errors must be reduced to a minimum • This can be done by: • Careful working • Using standard solution • Using a blank • Standard solution: • Should be included in all measurements • Should be treated in an identical manner to the fluids under investigation • Function: provides a useful check on the accuracy of a method

  5. Standard and blank (cont’d) • Blank solution: • Should be included in any measurement • The same volume of distilled water replaces the substance to be estimated • Should be treated in exactly the same way as the test and standard • Function: provides a useful check on the reagents purity • The function of standard and blank: to correct the obtained value Several blanks and controls need to be used when working with enzymes

  6. Glassware

  7. Macam Glassware • Pipet gondok (Volume pipette) • Pipet ukur (Graduated pipette) • Pipet tetes (Pasteur pipette) • Pipet mikro • Labu godog (Digestion flask) • Labu ukur (Volumetric flask) • Labu pemisah • Gelas piala (Beaker glass) • Botol timbang • Gelas arloji • Gelas ukur (Measuring cylinder) • Erlenmeyer (Erlenmeyer flask) • Buret makro • Buret mikro • Buret semimikro

  8. Cleaning glassware • Grease  rag soaked in chloroform or benzene and soaking overnight in chromic acid • Very dirty apparatus  soaking in a mixture of concentrated nitric and sulphuric acids • After rinsing in tap water followed by several rinses in distilled water • Normal glassware  dried in an oven • Volumetric glassware  rinsed with alcohol then dried warm air

  9. Terima kasih …

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