Laboratory Basics

1. 1 Laboratory Basics

2. Objectives Level I • Identify two methods used to produce clinical laboratory-grade water for use in the clinical laboratory. • List three items that should be monitored during the water-purification process. • Identify four types of glassware available for laboratory use.

3. Objectives Level I • Identify four types of plastics used in laboratory plasticware. • Define the following terms: to contain (TC) and to deliver (TD) in reference to types of pipettes, molarity, molality, normality, thermocouple, percent solution, and hydrates.

4. Objectives Level I • Cite three types of balances used to weigh substances in the laboratory. • Complete the mathematical calculations presented in this chapter correctly. • Convert results from one unit format to another. • Calculate the volumes required to prepare1:2, 1:5 and a 1:10 dilution.

5. Objectives Level II • Explain the difference between air-displacement and positive-displacement micropipettes. • Distinguish swinging-bucket, fixed-angle-head, and ultra centrifuges from one another. • Explain the usefulness of liquid-in-glass, total-immersion, and partial-immersion thermometers.

6. Objectives Level II • Identify three alternative thermometers that do not contain mercury. • Distinguish density, specific gravity, and assay by weight from one another. • Identify a source of calibration material for balances, thermometers, and pipettes.

7. Water Purification • Reverse Osmosis • Process by which H2O is forced through a semipermeable membrane that acts as a molecular filter • Distillation • Process by which a liquid is vaporized and condensed to purify or concentrate a sustance or separate volatile substances from less-volatile substances • Resistivity • Is the electrical resistance in ohms measured between opposite faces or a 1.00-cm of an aqueous solution at a specified temperature. • Used to assess the ionic content of purified water • ↑ ion concentration, ↓ resistivity

8. Laboratory Chemicals • Chemical grades • ACS • Reagent • Analytical • Pharmaceutical grades • The United States Pharmacopoeia (USP) • The National Formulary and The Food Chemical Index

9. Laboratory Chemicals • IUPAC • Grades A – E • National Institute of Standard and Testing (NIST)

10. Laboratory Glassware and Plasticware • Glassware • Borosilicate (High degree of thermal resistance, low alkali content, free of heavy metals) • Low actinic (High thermal resistance, amber or red color protect light sensitive materials) • Plasticware • Polypropylene (plastic pipette tips) • Polystyrene (capped graduated tubes, test tubes) • Polycarbonate (tubes for centrifuge, graduated cylinders, flasks; -100 to +160C) • Teflon (stirring bars, tubing, cryogentics vials, bottle cap liners)

11. Figure 1-1 Types of glass containers. A. Transparent glass; B. low actinic glass.

12. Volumetric Laboratoryware • Pipettes • TD (to deliver) • TC (to contain) • Micropipettes (air-displacement and positive-displacement) • Pipette calibration (accuracy&precision; weighting of water) • Volumetric flasks • Calibration of volumetric flasks

13. Figure 1-2 Several examples of glass pipettes. A. 0.2 mL TC; B. 1.0 mL TD serologic (blowout); C. 2.0 mL TD volumetric; and D. 10.0 mL TD Mohr. Note the two frosted- or etched-glass rings on pipette B.

14. Figure 1-3 Several examples of micropipettes used in clinical laboratories.

16. Balances Types Unequal-Arm Substitution Balances  Magnetic Force Restoration Balance Top-Loading Balances Electronic Balances Calibration

17. Figure 1-4 ASTM standard weight set used to calibrate laboratory balances.

18. Centrifuges • Relative centrifugal force and revolutions per minute • Types • Swinging bucket centrifuge • Fixed angle rotors • An ultracentrifuge • Refrigerated centrifuge • Maintenance and calibration

19. Figure 1-5 Schematic showing the three major components of a typical laboratory centrifuge.

20. Figure 1-6 Examples of two types of laboratory centrifuges. A. Swing-out rotor with buckets.

21. Figure 1-6 (continued) Examples of two types of laboratory centrifuges. B. fixed-angle rotor.

22. Water Baths • Types • Circulating • Non circulating • Maintenance and quality control

23. Mixing • Types • Single-tube mixers • Multiple-tube mixers

24. Figure 1-7 Two types of tube mixers. A. vortex mixing.

25. Figure 1-7 (continued) Two types of tube mixers. B. rocking motion of single and multiple tubes.

26. Thermometry • Types • Mercury free thermometers • Organic red-spirit and pressurized with nitrogen gas • Blue biodegradable liquid (isoamyl benzoate and dye) • Red liquid thermometer filled with kerosene • Bimetal digital thermometers • Digital thermometers with stainless steel stems • Partial immersion thermometers • Full immersion thermometers

27. Thermometry • Thermistor • Thermocouple • Thermometer calibration

28. Figure 1-8 Four examples of commonly used temperature monitoring devices. A. Mercury-filled partial immersion thermometer; B. red-spirit–filled partial-immersion thermometer; C. red-spirit–filled, total-immersion refrigerator thermometer.

29. Figure 1-8 (continued) Four examples of commonly used temperature monitoring devices. D. digital type with thermocouple.

30. Laboratory Mathematics • Systems of measurement • Metric • Length = meter • Mass = gram • Volume = liter • Le Système International d’ Unitès

31. Laboratory Mathematics • Temperature • Celsius • Fahreheit • Kelvin • Pressure • PO2 and PCO2 • Torr; Pascal

32. Metric Prefixes

33. The Base Units of the Le Système International d’ Unitès

34. Solution Concentrations • Dilutions • Density; Specific Gravity; assay by weight • Atomic Mass Unit; Moles • Molarity • Normality • Percent solutions • Hydrates • Enzymes

35. Acids and Bases • pH • Buffer solutions