Lab glass cleaning


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Advice and tips for clean and residue-free lab glass and laboratory equipment - cleaning agents and cleaning process

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Lab glass cleaning

  1. 1. Lab Glass Cleaning .com comAdvicefor clean andresidue-freeresidue freelaboratoryequipment © Dr. Weigert & DURAN Group 2012
  2. 2. Good practice– type of glass .comSelection of right types of glass a high quality of the raw materials and their composition ii wall thickness distribution in order to attain a good resistance to temperature and g p changes in temperature, high level of mechanical stability a very high hydrolytic resistance (corresponds to class 1 according to ISO 719). very small expansion coefficients, a high level of resistance to quick changes in temperature © Dr. Weigert & DURAN Group 2012
  3. 3. Good practice– conformity to standards .com• Why should attention be paid to conformity to standards? standards set the properties and geometries for laboratory glass products -> products can be still be obtained with the same characteristics and dimensions even after many years characteristics which are decisive for safety such as distribution of wall thickness in beakers, are given in the standards for many articles © Dr. Weigert & DURAN Group 2012
  4. 4. Good practice– instruction for use .com• What is important when selecting a glass item for use? before each use the glass surface should be checked for damage such as scratches, cracks or chips vessels should only b used when they are in l h ld l be d h h a flawless condition, this is particularly important for work under pressure or at high temperatures damaged glass may not be used for safety reasons. © Dr. Weigert & DURAN Group 2012
  5. 5. Cleaning – cleaning process .comThe advantage and disadvantages of• manual cleaning greater risk of injury slower and less economical when there are lots of items to be washed time consuming when the laboratory appliances have a complex geometry is clearly quicker if only single laboratory glass items are being cleaned flexible in terms of duration of cleaning and selection of cleaning agent © Dr. Weigert & DURAN Group 2012
  6. 6. Cleaning – cleaning process .comAdvantages and disadvantages of• cleaning in a washer/disinfector reduced breakage risk reduced risk if injury saves staff resources quicker and more economical for large quantities of items to be washed inflexible in terms of duration of cleaning and selection of cleaning agent © Dr. Weigert & DURAN Group 2012
  7. 7. Cleaning – type of soiling .comType of soiling• Organic soiling peptides/ proteins, fats/oils, carbohydrates/ polysaccharides, organic colourings, pigment residues colourings and felt tip residues, resins and paraffin © Dr. Weigert & DURAN Group 2012
  8. 8. Cleaning – type of soiling .comType of soiling• Inorganic soiling g g carbonates, salts, metal oxides, watery solutions of inorganic acids (HCl, (HCl H2SO4)/ alkali (NaOH, KOH), salt solutions (NaCl, NaNO3, FeCl2 etc.) © Dr. Weigert & DURAN Group 2012
  9. 9. Cleaning – type of soiling .comType of soiling• Microbiological residue g growth media, cell cultures and tissue residues, nutrient broth, microorganisms i i © Dr. Weigert & DURAN Group 2012
  10. 10. Cleaning - cleaning agents .comWhich cleaning agents are suitable for which soiling?• Alkaline cleaning agents are suitable f th d t i and removal it bl for the denaturing d l of residues which contain protein, fat and carbohydrates• Acid cleaning agents are effective against inorganic salts, lime and other carbonates.• Bleaching agents help with the removal of paints and with disinfection. © Dr. Weigert & DURAN Group 2012
  11. 11. Cleaning - cleaning agents .com• What requirements must a cleaning agent meet? The selection is linked to the type of soiling to be b removed and th f d d the framework conditions (ti k diti (time, material properties and mechanical system, quality of water) fundamental requirements: • Which resources can be used? good ability to remove dirt abrasive materials (steel wool) high dirt carrying capacity dirt-carrying must not be used -> these will suitable for most surfaces cause surface damage to the good rinsing properties g gp p glass not hazardous to health  soft sponges, cloths and brushes very cost-effective are suitable environmentally friendly © Dr. Weigert & DURAN Group 2012
  12. 12. Cleaning – parameters of cleaning .com• Chemistry (=cleaning agents) helps with the decomposition of dirt components and th simplifies t d thus i lifi the removal of dirt from surfaces the surfactants contained in cleaning agents improve the wetting of the item to be cleaned and the dirt-carrying capac ty o the ate capacity of t e water the selection of the cleaning agent to be used depends on the dirt to be removed, removed the material of the items to be cleaned and the quality of water used for automated cleaning © Dr. Weigert & DURAN Group 2012
  13. 13. Cleaning – parameters of cleaning .com• Temperature high temperatures can accelerate physical, chemical and enzymatic processes and h i l d ti d thus benefit removal of contaminations temperatures which are too high can, however, reduce enzyme activity Another disadvantage of excessive temperature is the i th conversion of carbonic acid contained i i f b i id t i d in the water to carbonate via hydrogen carbonate which is then precipitated as a poorly soluble compound with the water hardening salts magnesium and calcium. This results in stubborn ‘lime deposits’. © Dr. Weigert & DURAN Group 2012
  14. 14. Cleaning – parameters of cleaning .com• Time an extended reaction time for the cleaning solution makes th removal l i l ti k the l of dirt from the surface easier due to better swelling of the contaminants and a stronger chemical decomposition of the dirt components © Dr. Weigert & DURAN Group 2012
  15. 15. Cleaning – parameters of cleaning .com• Mechanics The use of mechanical agents such as the use of b h or pressurized water jets f brushes d enables bonding forces between dirt and surface to be overcome so that dirt can then be removed more easily. Chemistry temperature, time and mechanics are the four components Chemistry, temperature of the so-called Sinner’s Circle which describes the mode of action of the cleaning process and which was named after the chemist Dr. Herbert Sinner. Sinner © Dr. Weigert & DURAN Group 2012
  16. 16. Cleaning – Dr. Sinner´s Circle Sinner s .comDr. Sinner’s CircleEach parameter is variable in size. However, if one factor is changed thiswill affect the size of at least one other factor if the cleaning performanceis to remain the same. This means that a longer reaction time is necessaryif there is a lower temperature in the rinsing process for example. Areduced parameter is thus compensated by the increase of another. © Dr. Weigert & DURAN Group 2012
  17. 17. Cleaning – quality of water .comQuality of water defines • microbiological factors (germ count) • the degree of water hardness, given in °GH (German hardness) (magnesium and calcium ions in the water ) If water with a high degree of hardness is used for cleaning, significant residues may be deposited on the cleaned surfaces Depending on the water quality (e.g. deionised water or softened water) different effects are achieved in combination with the used cleaning agents. These affect the material compatibility and the cleaning results. © Dr. Weigert & DURAN Group 2012
  18. 18. Advice and Tips .com• How can laboratory glass be stored correctly whilst saving as much space as possible?• Marking – what has to be observed?• How can stubborn residues be avoided?• How should the glass be disposed of?• What should you know about volumetric glassware?• How should you clean cover glass and slides? All this and more at : © Dr. Weigert & DURAN Group 2012
  19. 19. Laboratory Glass Cleaning .com From experts for experts – p p © Dr. Weigert & DURAN Group 2012 Pictures by Karin Gerdes © Dr. Weigert & DURAN Group 2012