Lecture (week2) Flashcards
preferred in
scientific literature and clinical laboratories and is the only system used in many countries
o Accepted internationally
o Provides global scientific community a uniform method of describing physical quantities
Système International d’Unitès (SI)
o Derivative or a mathematical function of one of the
basic units
o Example: m/s; still from base unit; can be
expressed using different parameter
Derived unit
o Widely used that they have become acceptable for
use with SI basic or SI derived units
Some Non-SI units
o When added to a given unit, it can indicate decimal
fractions or multiples of that unit
o Important note:
▪ The SI term for mass is kilogram or Kg. It is
the only basic unit that contains a prefix as
part of its naming convention
SI uses standard prefixes
- Electronic transmission of laboratory data and the more routine use of an electronic medical record, coding,
billing, and other data management systems may vary.
o Varies from one institution to another. Depends on
the SOP.
ELECTRONIC REPORTING OF RESULTS
- A substance that is used to test for the presence of another substance by causing reaction with it.
- Any substance employed to produce a chemical reaction
REAGENTS
substances that occurs naturally or is obtained through a chemical process. These analytical chemicals used in
the laboratory exists in varying grades of purity.
CHEMICALS
I. Analytical Reagent (AR)
II. Ultrapure
III. Chemically Pure (CP)
IV. United States Pharmacopeia (USP)
V. National Formulary (NF)
VI. Technical or Commercial Grade
CHEMICAL GRADES OF PURITY (INORGANIC REAGENTS)
o Highest grade of purity
o Established by ACS- American Chemical Society
o used for qualitative and quantitative analysis in
the laboratory
o used for special testing in the lab: trace metal
analysis and preparation of standard solutions
Analytical Reagent (AR)
o Additional purification which could be more sensitive
o Used for chromatography, atomic absorption spectrophotometry, molecular assays, molecular diagnostic for standardization, or other techniques
that require extremely pure chemicals
Ultrapure
o Pure grade
o Purity of the chemical is specified by the
manufacturers
o Chemically pure substances fail to reveal the tolerance limit of its impurities
o Not intended for research and analytical chemistry
Chemically Pure (CP)
o Pure enough to use in most chemical procedures however, it should be recognized that the purity standards are not based on the needs of the laboratory.
o May or may not meet all assay requirements.
o Good for human consumption
o Used in drug manufacturing
United States Pharmacopeia (USP)
o Same characteristics as USP
National Formulary (NF)
o Not used in clinical laboratory testing and only used in manufacturing industry
Technical or Commercial Grade
Also have varying grades of purity that differs from those used to classify inorganic reagents
Organic Reagents
o Practical grade with some impurities
o Chemically pure
o Spectroscopic
o Chromatographic
It approaches the purity level of reagent
grade
Chemically pure
Spectrally pure
Spectroscopic
The minimum purity of 99% could be
obtained only by gas chromatography
Chromatographic
o highly purified chemical that can be measured directly to produce a substance of exact known concentration and purity; purest
o ACS purity tolerance test for primary standard should be 100% ± 0.02%; equal to perfection
o Most biologic constituents are unavailable within
this limitation
Primary standard
Used in place of an ACS primary standard in clinical work and is often used to verify
calibration or accuracy of assessment/testing
NIST: Standard/Certified Reference Material (SRM/CRM)
o substance of lower purity with concentration determined by comparison with a primary standard
o prepared solution whose concentration is determined by testing
Secondary Standard
the most frequently used reagent in the
laboratory.
Water
o Distillation (distilled water)
o Ion exchange (deionized water)
o Reverse Osmosis
o Other purification processes: Ultrafiltration,
Ultraviolet Light, Sterilization, Ozone Treatment
Purification
o Classification according to CLSI as: Clinical laboratory reagent water (CLRW), Special reagent water (SRW), Instrument feed water, Water supplied by method manufacturer, Autoclave and wash water, and commercially
bottled purified water.
Reagent Grade Water
remove particulate matter for municipal
water supplies before any additional treatments
o Glass, cotton (to filter more particulate matter), activated charcoal (remove organic materials, even chlorine), submicron filters (≤ 0.2 mm; remove substances like bacteria)
Prefiltration
water has been purified to remove almost
all organic materials
o Water is boiled and vaporized.
o Water can be distilled more than once with each distillation cycle removing additional impurity
Distillation
water has some or all ions removed
o Although ions are removed, organic materials may
still be present
o If water goes ion exchange treatment, it is neither
pure nor sterile
Ion exchange
process that uses pressure to force
water through a semipermeable membrane
o Water that reflects a filtered product of the
original water is an RO water
o In RO, it does not remove dissolved gasses.
o At most cases, reverse osmosis may be used
as a pre-treatment of water.
Reverse Osmosis
excellent in removing particulate matter, microorganisms, and any pyrogens or
endotoxins
o Through ultraviolet oxidation, organic materials are removed. Sterilization processes, together with ozone treatment, removes bacteria, other microorganisms, or other residual products
Ultrafiltration & Nanofiltration:
Most pure
- ideal for special testing in the laboratory; trace metal determination, ion determination, enzyme analysis, tissue or cell culture, and the likes. Silicate content and resistivity goes hand in hand. The less
silicate content, the more the water is resistant. The more the water is resistant (less conductive), the more the water is pure.
Type I
still acceptable in most analytical requirements. Used in
quality control, reagent preparation, and laboratory determination.
Type II
Type III
not ideal for analysis or reagent preparation
Analytical reactions occur in optimal temperatures.
o Liquid in glass: usually measure temperatures between 20°C and 400°C
o Electronic / Thermistor probe: smaller and has millisecond response time
o Digital
Thermometers
are calibrated in the laboratory to make sure that accurate temperature is obtained. Calibrator: gallium
Thermometers
Differ on their ability to resist acid and alkaline solution and thermal resistance.
Glassware
▪ Ideal for heating and sterilization processes
▪ Has high thermal resistance
▪ Example: Pyrex, Kimax
Borosilicate Glass
▪ Soda lime glass
▪ Inexpensive but has low resistance to
temperature and chemical
▪ Easy to melt
▪ Usually, a disposable glassware (petri dish)
Flint Glass
▪ Silica glass
▪ Quite expensive
▪ Used when excellent light transmission is
needed
▪ Used for cuvettes (holds solution in
spectrophotometer)
Quartz Glass