Lecture 1 Flashcards

Question

S T A N D A R D S O L U T I O N S

Answer 1

Requires a high degree of accuracy * Standard= solution of exact known concentration * Used as a reference to determine the concentration of solutions of unknown concentrations * Equipment: analytical balances and volumetric glassware volumetric (quantitative) transfer preparation Primary Standards-dissolving an exact amount of pure dry chemical in a solvent and diluting to an exact, known volume so concentration is determined by the weight of solute in an exact volume of solution. - be at least 0.9995 (w/w) [99.95% (w/w)] pure * have a stable and definite composition * be non-hygroscopic and remain unchanged in composition when dried in hot air oven at 105-110C (before use) and put in a dessicator * preferably have a high molecular weight * react stoichiometrically* in a single, rapid, complete reaction potassium acid phthalate sodium chloride TRIS Secondary Standards- all criteria from primary cannot be met .The concentration of a secondary standard is determined by analysis against a primary standard by * titrametric analysis * spectrophotometry Sodium hydroxide (NaOH) Concentrated Acid/Base or Viscous Fluid Biological Standards- bili, chol, hormones primary and secondary are different in how their concentrations are determined

Answer 2

* Reagent name and concentration * Date of preparation * Initial of person who prepared the solution * Expiry date (if applicable) * WHMIS label be sure to check the shelf life

Answer 3

Water treated to remove impurities Special reagent water used for clinical lab applications meeting clinical laboratory reagent water (CLRW) specifications. Prepared by distillation, deionization, reverse osmosis, UV light treatment Testing water purity: Includes specific guidelines and specifications from CLSI * CLRW: resistivity (≥10 Mohm

Answer 4

highest purity, used for maximum accuracy and precision use immediately - no storage instructions

Answer 5

- less pure than Type I, used for general laboratory procedures Distilled water: * water collected from the process of vapourizing water to steam and condensed back to liquid * Free from all non-volatile materials, some volatile organic matter, dissolved gases and trace amounts of ions, ex: Na+ , K+ , CO3 * pH 6.5-7.0 Deionized water: * Water collected from an ion exchange column tightly packed with chemically attached resin beads that act like a cation and anion exchanger. * Free of ionic impurities * pH 7.0

Answer 6

- least pure of the three, used for qualitative procedures

Answer 7

supplier labels * workplace labels * A workplace label is required when: * a hazardous product is prepared * a hazardous product is decanted (e.g., transferred or poured) into another container, or * a supplier label becomes lost or illegible (unreadable)

Answer 8

* Two situations when a workplace label is not necessary: * When a hazardous product is: * poured into a container which is going to be used immediately, or * under the control of the person who decanted it Note: If the product is not used right away or if more than one person will use the product, a full workplace label is required.

Answer 9

* Degree or level of hazard of the product * Two signal words: * Danger * Use for high-risk hazards * Warning * Used for less severe hazards

Answer 10

when hydrates upon exposure to air give up their water of crystallization

Answer 11

Chemicals which are so hygroscopic that they can absorb water from other chemicals anhydrous calcium chloride * anhydrous magnesium perchlorate * calcium sulphate (drierite) * silica gel

Answer 12

* Laboratory Centre for Disease Control (Ottawa) * National Bureau of Standards (NBS) * World Health Organization (WHO) * National Institute of Health (NIH).

Answer 13

has undissolved solute existing in a state of dynamic equilibrium with dissolved solute contains the maximum amount of solute that can be dissolved at a given temperature - 20 (room temp) when making a standard solution determine solubility at room temp, find out how much you need for the solution , WEIGH OUT EXCESS , HEAT solute and solvent until solute is dissolved , remove from heat and cool all extra solute will crystallize at room temp if not then supersaturated just add some crystals to start the process

Answer 14

A buffer is a solution which resists changes in pH. 1. a weak acid or a weak base 2. the salt of that weak acid or weak base. when making a buffer add the acid/base with salt and ALMOST to full volume check the pH make adjustments if needed and then dilute to full volume

Answer 15

Always place the proper lid back on the reagent bottle immediately after use. Never pipette reagent directly from a stock bottle Never pour unused reagent back into a stock bottle Never use your fingers for handling Never mix tubes MIX ACID TO WATER

Answer 16

purest grade of chemicals used for routine clinical analysis qualitative and quantitative analysis in the laboratory American Chemical Society (ACS) - must meet their specs ACS on label

Answer 17

meet no particular purity specifications impurity limits not listed some make their own "highest purity" not for research but ok for routine analysis

Answer 18

have to be further purified before use not for analytical procedures

Answer 19

least pure manufacturing in the lab ONLY for acid washing glassware, desiccants, neutralize acid spills

Answer 20

safe for injection or ingestion into the human body. NF, BP, CP, USP not be used in analytical procedures

Answer 21

Determination of Melting Point, Freezing Point, or Boiling Point Spectrophotometry - Spectral Absorbance Curves- wavelength the chemical absorbs light . chemical after this are spectroanalyzed. Molar Absorptivity -The absorbance of a one molar solution through a one cm light path Chromatography- separate mixtures of various components. if something is pure only one thing will show on the graph

Answer 22

Store concentrated acids and bases in separate cupboards, well vented and low to the floor. Flammable liquids in safety cans for expansion Poisons such as barbiturates and cyanides should be kept in a locked cupboard Ethers should be stored in the fume hood in safety cans- explosive Picric acid is explosive when dry and should always be stored under a layer of water Radioactive isotopes in lead containers

Answer 23

vaporizing water to steam, and condensing the steam on a cold surface back to water which is collected removes ions , non volatiles, water stored in polyethylene or pyrex containers to prevent contamination , soda glass will have trace metals

Answer 24

removal of ionic impurities but non ions are still in the water passed through an ion exchange column which is tightly packed with resin (polymer) beads cations exchange for H+ anions exchange for OH- if it has both cationic and anionic resin exchangers is called a mixed-bed ion exchange column. water stored in polyethylene or pyrex containers to prevent contamination , soda glass will have trace metals

Answer 25

Ultraviolet Light -bactericidal Reverse Osmosis-water is forced at high pressure through a semi-permeable membrane. Cant produce CLRW on its own but good to have Carbon Adsorption- passing water through a bed of activated carbon, Filtration- water is passed through a filter which mainly removes solid impurities

Answer 26

SPECIFIC RESISTANCE/SPECIFIC CONDUCTIVITY -measure of the resistance of water to the passage of a current between two electrodes. Ionized material = conductivity increase = low specific resistance. No material high resistance. So the higher the resistance the purer the water ORGANIC SUBSTANCES looking for presence of organic material by detecting products of oxidation by UV light, heat, high temp - can also use permanganate colour test to detect presence of organic substances, The more color that is lost the more substances present.