Chemistry week 1 Flashcards
first laboratory attached to a hospital
Munich, Germany: Hugo Wilhelm von Ziemssen (1895)
William Pepper Laboratory of Clinical Medicine at University of
Pennsylvania (Philadelphia).
US
looked back on experiments of Antoine-Laurent
de Lavoisier in pneumatic chemistry
Henry bence Jones
“few and scanty, indeed, are the
rays of light which chemistry has flung on the vital mysteries.”
Robert James Graves (1796–1853)
– first used the term “clinical
chemical laboratory” (“klinisch-chemischen Laboratorium”)
Johann Joseph Scherer (1814– 1869)
– complained that clinicians
do not use their chemistry laboratory services except when needed for
“luxurious embellishment for a clinical lecture,”
Max Josef von Pettenkofer (1818–1901)
defined as the measurement system used in many
countries such as the United States using pounds, yard, miles, pint, etc
English system
derived from the Greek word “metron” meaning
“measure”. This system of measurement is used in scientific work
which includes gram, meter, and liter.
Metric system
Reporting of laboratory results is often expressed in terms of
Substance concentration or mass of the substance
- It is the modern form of the metric system and is the world’s most
widely used system of measurement; used in both everyday commerce
and science. - Preferred in scientific literature and clinical laboratories
- Consists of seven independent base units, each unit represented by a
symbol
System international
Seven base of SI Units
Length -
Mass -
Time -
Quantity of substance -
Electric current -
Thermodynamic temperature -
Luminous intensity -
Length - Meter
Mass - Kilogram
Time - Second
Quantity of substance - Mole
Electric substance - Ampere
Thermodynamic temperature - kelvin
Luminous intensity - candela
Substance being dissolved
Solute
Substance in which the solute is dissolved
Solvent
Weight or volume of the solute present in a specified amount of the solvent or solution
Concentration of solution
Weight in volume percent solution (W/V)
Grams of solute (g) / volume of solution X 100
Volume in volume percent solutions (V/V)
Volume of solute (g) / Volume of solution X100
Weight in weight percent solution (W/W)
Grams of solute (g)/ Grams of solution X 100
Molarity
Number of moles of solute/ volume of solution in liters
OR
Mass of solute in grams/ MW of solute X volume of solution (L)
Molality
Moles of solute/ Mass of solvent in kilograms
OR
Mass of solute in grams/ MW of solute X mass of solvent (kg)
The combining capacity or power of an atom of an element compared to hydrogen whose combining capacity is taken as one
Valence
number of units that can replace 1 mole of HYDROGEN ions
Acid
number of units that can replace 1 mole of HYDROXYL ions
Base
Normality
molarity X valence
or
grams of solute/ volume solvent in liters X EW
Dilution
C1V1 = C2V2
Cab be heated up to 400-500c
Resistant to heat, corrosion, and thermal shock
Used when heating or sterilization is required
Borosilicate glass
Six times stronger than Borosilicate. Can be heated up to 800C
Corex
Acid and alkali resistant
Can be heated to 900C
Vycor
Most common resistant Borosilicate glassware in the laboratory
Beakers, Flasks, Pipettes
Made by removing all elements from borosilicate glass
Has good optical qualities, temperature capabilities, and is radiation-resistant
Not used for the type of glassware in the laboratory
High silica glass
Partially used for strong ALKALINE solution
Referred to as soft glass because it’s thermal resistance is much less than borosilicate glass
Used for digestion with strong ALKALI is made
For strong BASIC solution
High Alkali-Resistant glass
Amber container for solutions that can be deteriorated with light
Low actinic glass (actinic meaning relating to or denoting light able to cause photochemical reactions)
Used for the manufacture of weighing bottles
Develops less static surface changes
Poor resistance to high temp
Composed of mixture of the oxides of silicon, calcium, and sodium
Standard flint glass / Soda-lime glass
Used in light fitters, lamp bulbs, and lightning lenses
“Stained glass”
Colored and Opal glasses
Have thin metallic oxide permanently fine-bonded to the surface of the glass
Electronic application as heat shield to protect against infrared light
Coated glass
Mostly soda-lime, lead, and borosilicate of high optical purity
Used in making prisms, lenses, and optical mirrors
Optical glasses
Have higher thermal resistance, chemical stability, and corrosion resistance like borosilicate glasses
Useful in hot plates, tabletops, and heat exchanges
Glass ceramics
Made of soda-lime and lead
Useful in preventing transmission of huge energy radiation as gamma ray and x-rays
Radiation-absorbing glasses
Beginning to replace glassware in the laboratory setting
unique high resistance to corrosion and breakage as well as its varying flexibility, had made it most appealing
Inexpensive
Disposable to avoid carry-over contamination
Plastic wares
Unique group of resins with relatively inert properties
Unaffected by acids, alkalis, salt solutions, and aqueous solutions
Can be autoclaved
Polyolefins
Most common light source that has iodine or bromine vapor
Tungsten Iodine lamp
contains small amounts of halogen such as
iodine to prevent the decomposition of the vaporized tungsten from the very hot filament. Have fuse silica envelop which could provide high intensity of UV Light
Quartz Halide lamp
provides energy source with high output
in the UV range (down to 165 nm). Most commonly used for UV work.
Deuterium discharge lamp
used above 800 nm
Infrared Energy source
Wavelength of visible light
340-700 nm
Below 340 nm wavelength
Ultraviolet
Above 700nm wavelength
Infrared region
An electrically heated rod of rare earth element oxides
Merst glower
Uses silicon carbide
Globar
Exits narrow bands of energy at well-defined places in the spectrum (UV and Visible)
Mercury vapor lamp
Emits sharp line spectrum
Low pressure mercury lamp
Emits continuous spectrium
Medium and High-pressure Mercury lamp
Consists of a gas-tight chamber containing anode, a cylindrical cathode, and insert gas such as helium or argon. LIGHT SOURCE OF Atomic Absorption Spectophotometry
Hollow Cathode lamp
Minimizes unwanted or stray light and prevents the entrance of scattered light into the monochromator system
Entrance Slit
Isolate specific wavelength of light
Monochromator
Wide band pass filters (SB of 50nm).
Glass filters
Used to eliminate light below a given wavelength
Sharp Cut-Off types
Use dielectric material of controlled thickness between 2 thinly silvered pieces of glass
Narrow band pass
Lease expensive, pass a relatively wide band of radiant energy and have a low transmittance of the selected wavelength.
Not precise but inexpensive, simple, and useful
Colored glass filter
Colored glass filter band pass
35-50nm or more
Utilizes the wave character of light to enhance the intensity of the desired wavelength by constructive interference and eliminates other by destructive inference and reflections
Interference filter
Interference filter band pass
10-20nm
Wedge-shaped pieces of glass, quartz, NaCl, or some other material that allows transmission of lights
Disperse the white light into continuous spectrum of colors
can be rotated, allowing the only desired wavelength to pass through an exit slit
Prisms
Most commonly used monochromators
Produce linear spectrum or orders directed towards the exit slit and may need accessory filters for stray light
Prepared by depositing a thin layer of aluminum copper alloy
Diffraction gratings
Controls the width of light beam
Exit slit
Used to hold the solution in the instrument whose concentration is to be measured.
Cuvette/ Sample cell / Analytical cell
Cuvettes for solutions that do not etch glass
Borosilicate glass cuvette
Cuvettes that does not absorb UV radiation below 320nm
Quartz or plastic cuvette
Cuvettes that are good for 340 nm and above
Alumina Silica glass
Electron tube amplifying a current that can convert transmitted energy into an equivalent amount of electrical or photoelectric energy
Detectors (Photodetectors)
Most commonly used detector
Uses a series of electrodes to internally amplify the photo signal before leaving the tube
Photomultiplier tube
Simplest method of displaying output of the detection system
Meter
Used to check the wavelength accuracy
Didymium and holmium oxide filter
Verifies the absorbance accuracy on linearity
Neutral Density filters and Dichromate solution
Uses TWO photodetectors, for the sample beam and reference beam
Double beam in Space
Uses ONE photodetector and alternately passes the monochromatic light through the sample cuvette and then reference using a chopper
Double beam in time
The Principles are
* Measures concentration of element by detecting absorption of
electromagnetic radiation by atoms, rather than by molecules.
* The element is not excited but they are dissociated from their chemical
bonds and placed in the unionized, unexcited ground state.
* It is ideal for alkali metals that are not easily excited (e.g. calcium,
magnesium).
* Uses propane acetylene for flame emission
Atomic absorption spectrophotometry
Selects the desired wavelength from a spectrum of wavelength which could either be a prism or diffraction gratings
Monochromator
Uses photomultiplier tubes to measure the intensity of the light signal
Detector
- Instrument modification: electric furnace to break chemical bonds
(electrothermal atomization) - Tiny graphite cylinder
- Electric current -> cylinder walls -> evaporates the solvent -> ashes the
sample -> heats the unit to incandescence to atomize the sample - Deuterium Lamp – secondary source (background correction)
- Zeeman Effect – presence of an intense static magnetic field will cause
the wavelength of the emitted radiation to split into several
components
Flameless AAS
Used in tandem with mass spectrometry
Inductively coupled plasma
Measurement of emitted light when an electron in an atom becomes excited by heat energy produced by the flame
Filter photometry, Flame emission spectrophotometry or Flame emission photometry
The unknown sample is made to react with a known solution in the presence of an indicator
Volumetric (Titrimetry)
Schales and Schales
Chloride determination
EDTA titration
Calcium determination
It is the solution of the pure form of the sample and its derivatives and the determination of its dry weight
Gravimetric
Determines the amount of light emitted by a molecule after excitation by electromagnetic radiation
Fluorometry
The chemical reaction yields an electronically excited
compound that emits light as it returns it to its ground state, or that transfers its energy to another compound, which then produces
emission
Chemiluminiscence
Measurement of the light BLOCKED by a suspension of a particulate
Turbidimetry
It is the measurement of light SCATTERED by a small particles at an angle to the beam incident on the cuvette
Nephelometry
Measures the disintegration per minute of time of a radioisotope
Scintillation counter
It is based on measuring changes in the colligative properties of solutions that occur owing to variations in particle concentration
Measure the osmolality of an aqueous solution
Osmometry
Separation of a mixture based on specific differences of the physical-chemical characteristics of the different components on a supporting medium called absorbent or sorbent
Chromatography
Measures the electrical potential due to the activity of free ions
Potentiometry
Sensitive and SELECTIVE for the ION it measures
Ion selective electrode
Measurement of amount of electricity at a fixed potential
Follows faraday’s law
Coulometry
Measurement of the amount of CURRENT that flows when a constant VOLTAGE is applied to the measuring electrode
Amperometry
measurement of DIFFERENCES in CURRENT at a CONSTANT VOLTAGE
Follows the Ilkovic Equation
Polarography
Measurement of the CURRENT FLOW between two NON-POLARIZABLE electrodes between which a known ELECTRICAL POTENTIAL is established
Conductometry
Measurement of the current after which a potential is applied to an electrochemical cell
Voltammetry
Migration or movement of charged particles in an electric field
Electrophoresis
Measures the concentration of solute particles in a solution
Osmometer
Glucose decreases by ___ % in 1 hour due to glycolysis of RBC in the sample
5-7%
Rate of decrease of glucose in Room temp
7mg/dL per hour
Rate of decrease of glucose in ref temp
1-2 mg/dL per hour
Choice of sample for glucose test
Sodium Fluoride
Maintains acidic pH of 4-5 to inhibit bacterial activity in 24H urine sample
5 mL glacial acetic acid
Requested during insulin shock and hyperglycemic ketonic coma
RBS
glucose load for non-pregnant px
75g
Glucose load for pregnant px
100g
Glucose load for a child px
1.75g /kg of body weight
Ferric Chloride + Acetoacetic Acid = Red Solution
Gerhardt’s Test
Acetoacetic Acid + Nitroprusside = Purple Color
Nitroprusside
Cupric Ions into Cuprous Ions
Copper reduction method
o Uses Phosphomolybdic Acid (PMA)
o Result to molybdenum blue
Folin Wu method
o Uses Arseno-molybdic Acid (AMA)
o Accurate but labor intensive and difficult to automate
o Cu2+ ->Cu+
o Cu+ reduces AMA to molybdenum blue
Nelson-Somogyi Method
Cu + Neocupreine = Yellow to Yellow Orange
Neocupreine Method
Copper reduction forms a Brick Red Solution
Benedict’s Method/Fehling’s Reagent
Ferric Ions into Ferrous Ions
* Inverse colorimetry which focuses on the disappearance of color
o Fe3+ → Fe2+
▪ Fe (CN)3 → Fe (CN)2
o Yellow → colorless measured at 400 nm
Ferric Reduction (Hagedorn Jensen)
o Most sensitive method
o Uses acetic acid heated at 100OC
o O-toluidine is carcinogenic and poisonous
o Absorbance read at 630 nm
o Glucose + O-Toluidine → Glycosylamine (Green) or Shiff’s Base
o Interferences: Maltose and Galactose
Dubowski Method (O-Toluidine Method)
Gold standard for glucose determination
Hexokinase method
Glucose + ATP > G6PO4 + ADP
Hexokinase method
Uses the principle of ion selective electrode
Clark electrode
H2O2 + Organic dye → Red to Violet Colored
Trinder’s method
▪ Uses Horseradish Peroxidase
▪ H2O2 → H2O + O2
Peroxidase method
Disadvantage of Glucose Oxidase Reaction
Interferences:
▪ Oxidizing Agents (Bleach or Detergent): False increase in
glucose level
▪ Reducing Agents (Uric Acid, Vitamin C): False decrease in
glucose level
Hexokinase method measures glucose at what wavelength
340nm
Building blocks of other lipids
Fatty Acid
Fatty acid storage and transport of metabolic interediates
TAG
membrane structure, membrane signal transduction, storage of arachidonic acid, component of pulmonary surfactant
Phospholipids
Membrane structure
Spingolipids
Metabolic fuel
Ketone bodies
Precursor for bile acids, and steroid hormones
Cholesterol
Fat soluble vitamins
Vitamins A, D, E, and K
2 major functions of lipids
Building blocks for TAG and phospholipid and Sources of metabolic energy
Non esterified form. Found in the circulation formed by the hydrolysis of the lysosomes
Free cholesterol
Covalently linked with one fatty acid that is also found in the circulation and is considered a neutral lipid
Esterified Cholesterol
Simplest glycolipids
Cerebrosides
Protein associated with the plasma lipoproteins
Regulates the plasma lipid metabolism by activating and inhibiting enzymes that are involved in the process
Apolipoproteins
Major component of HDL
Apo A
Major activator of LCAT
Apo A-1
Activates hepatic lipase
Apo A-II
Cofactor of LCAT
Apo A-IV
Major protein component of LDL
Apo B
Binds to LDL receptor
Apo B-100
Structural role in chylomicron
APO b-48
Major protein component of VLDL
APO C
Activates LCAT
APO C-I
Potent activator of LPL
Apo C-II
Regulates rate of clearance of TAG
APO C-III
Previously known as APO A-III
Serves as lysolecithin carrier
Apo D
Recognizes cell receptors to target chylomicrons and VLDL remnants to the hepatic receptor
APO E
Largest of the lipoprotein particles
Chylomicron
Lowest density (lipoprotein)
Chylomicron
Major carrier of exogenous triglyceride
Chylomicron
Creamy layer on top of fasting serum that has been cooled overnight indicates the presence of?
Chylomicron
Carry triglycerides from the liver to the cell
VLDL
Most atherogenic lipoprotein (bad cholesterol)
LDL
Synthesized in the liver and are responsible for transporting cholesterol from the liver to the PERIPHERAL TISSUE
LDL
Severe elevations of TAG and LDL will result into?
Pancreatitis
Good cholesterol
HDL
Gathers cholesterol from tissues for transport back into the liver (reverse transport)
HDL
Responsible for the mechanism of reverse transport
ABCA-1 (ATP- Binding cassette Protein A1)
VLDL remnant
Intermediate density lipoprotein
IVL migrates in what region in electrophoresis?
Pre-beta or Beta region
Sinking pre-beta lipoprotein
Lipoprotein (a) / LP(a)
Related with CHD
Lipoprotein (a) / LP(a)
Abnormal lipoprotein which is found in patient with obstructive jaundice
LpX
Floating beta lipoprotein
Beta VLDL
Contains Apo E
HDLc
Deficiency in B-D-Galactosidase
Krabbe’s disease
Deficiency in a-D-Galactosidase
Fabry’s Disease
Deficiency in B-D-hexaminidase A
Tay-Sach’s Disease
Deficiency in sulfatide sulfatase
Metachromatic Leukodystrophy
Deficiency in Sphingomyelinase
Niemann-Pick disease
Deficiency in B-D-Glucosidase
Gaucher’s Disease
TAG values
Normal: <150mg/dL
Borderline High: 150-199mg/dL
High: 200-499 mg/dL
Very high: >500mg/dL
o One step direct method (simplest approach)
o Cholesterol + H2SO4 + Glacial Acetic Acid + Acetic Anhydride =
Oxidation Products / Cholestedienyl Monosulfonic Acid (Green)
o Measure at 4 10 nm
o Other serum constituents such as hemoglobin and bilirubin
absorb strongly in this region and may produce falsely elevated
values.
Liebermann-Burchardt
End product is Cholestadienyl disulfonic acid (red end color)
Salwoski reaction
o Saponification → Extraction → Colorimetry (L-B)
o Precipitation of cholesterol esters after extraction separate
esterified from free cholesterol, permitting measurement of
only the free fraction
o Extraction: Specimen + Zeolite = Cholesterol
▪ Cholesterol esters → Hydrolysis → Free Cholesterol
Abell-Kendall Method
Reference method for cholesterol determination
GCMS
CDC reference method
Hydrolysis >
Extraction >
Leibermann-Buchard reaction
Hydrolysis > Alcoholic KOH
Extraction > Hexane
Leibermann-Buchard reaction
Interferences in cholesterol determination
Bilirubin
Ascorbic Acid
Hemoglobin
>5mg/dL Bilirubin
Hemolysis - falsely increased cholesterol
Increased or decreased cholesterol?
o Hyperlipoproteinemia Type II, III, and IV
o Biliary Cirrhosis
o Alcoholism
o Nephrotic Syndrome
o Primary Hypothyroidism
o Diabetes Mellitus / DM – poorly controlled
Increased cholesterol
Increased or decreased cholesterol?
o Severe Hepatocellular Disease
o Malabsorption Syndrome
o Hyperthyroidism
o Malnutrition
o Severe Burns
Decreased cholesterol
VLDL equation
TAG /5
Total cholesterol
HDL + LDL + VLDL
LDL if TAG <400
TC- (HDL+TAG/5)
LDL IF TAG IS >400
TC - (HDL+TAG X . 016)
LDL IF TAG IS MMOL/L
TC-(HDL+TAG/2.175)
VLDL if MMOL/L
Tag/2.825
VLDL if mg/dL
TAG/6.5
Cholesterol conversion factor
0.026
Tag conversion factor
0.0113
LDL Reference value
- Optimal: <100 mg/dL
- Near Optimal/Above Optimal: 100-129 mg/dL
- Borderline High: 130-159 mg/dL
- High: 160-189 mg/dL
- Very High: > 190 mg/dL
Total cholesterol reference value
- Desirable: <200 mg/dL
- Borderline High: 200-239 mg/dL
- High: > 240 mg/dL
HDL reference value
- Low: <40 mg/dL
- High: >60 mg/dL
