D9 drug detection and analysis

Question 1

what are steroids

Answer 1

lipids w 4 fused rings in structure – steriodal backbone

Question 2

2 examples of steriods
T-
C-

Answer 2

testosterone
cholesterol

Question 3

what is testosterone

Answer 3

male steroid hormones, performance enhancing drugs

Question 4

most common method for detection of steorids in blood? (for drug tests)

Answer 4

gas chromatography

mass spectrometry

Question 5

what does mass spec do vs gas chromatography

Answer 5

mass spec: identifies and quantifies the components

gas chromatography: seperates chemical mixture into pure chemicals

Question 6

3 steps for mass spectromatry

Answer 6

1. mass spectrometer vaporises the sample, generating positive ions from components
2. ions are accelerated an deflected in a magnetic field, seperated
3. molecules fragment intor structures identifiable by charge to mass ratio

Question 7

what does gas chromatography do

Answer 7

seperates the chemical MIXTURE into PURE chemicals

Question 8

what property of the mixture (urine) allows for gas chromatograpy

Answer 8

the components have different affinities for the stationary and mobile phase

Question 9

stationary vs mobile phase

Answer 9

stationary: microscopic layer of non-volatile liquid (usually polymer), coated on the walls of an inert solid support

mobile: inert carrier gas eg helium

Question 10

describe how gas chromatograpy works

Answer 10

1 components of mixture seperated – determined by diff rates at which they move thru the chromatography apparatus

2 rates differ bc boiling points and solubilities – determine relative associations with stationary and mobile phases (liquid and gas)

Question 11

what factors for the components matter for gas chromatograpy that determines whether theyre stationary or mobile phase

Answer 11

boiling point and solubility

molecules w more time in gas phase = move quicker
incr bp + incr sol = liquid = slower

Question 12

why is the temperature in the column controlled in gas chromatography

Answer 12

so some components condense and dissolve in the liquid (stationary) phase on the column walls

• changing temp controls retention times = changes amt of seperation

Question 13

what is retention time in terms of gas chromatography

Answer 13

the specific interval of time in which each component of the mixture is eluted

Question 14

name the 3 methods for organic structure analysis and identification

Answer 14

mass spectroscopy
infrared spectroscopy
proton NMR

Question 15

what is ethanol is breath

Answer 15

ethanol established equilibium in the lungs between the solution in the blood anf the gas released in exhaled breath

C2H5OH (aq) <=> C2H5OH (g)

Question 16

what instruments are used to measure ethanol conc in breath

Answer 16

breathalysers

alcosensor

Question 17

what type of reactions happen in breathalysers

Answer 17

redox

Question 18

what ions and reaction causes the colour change in breathalysers

Answer 18

ethanol oxidised by potassium dichromate (VI)

potassium dichromate (VI) reduced to chromate (III)

orange (VI) to green (III)
6 –> 3

Question 19

steps for breathalyser

Answer 19

1. ethanol oxidised by potassium dicromate 6
2. potassium dicromate 6 reduced to 3
3. orange to green
4. extent of colour cahnge measured w photocell - determines ethanol conc

Question 20

breathalysers are preliminary tests, which can lead to further testing using ?

Answer 20

intoximeters

Question 21

what is an alcosensor

Answer 21

an instrument that uses electrochemistry in a fuel cell to measure ethanol conc

Question 22

what reactions occur in an alcosensor when exhaled breath is passed over the cell

Answer 22

ethanol oxidised to ethanoic acid at anode

C2H5OH + H2O –> CH3COOH + 4H+ + 4e-

protons and electrons go to cathode, oxygen reduced to water
O2 + 4H+ + 4e- –> 2H2O

Question 23

electric current produced by the reactions in an alcosensor is used to calculate?

Answer 23

blood alcohol concentration

Question 24

what is blood alcohol concentrations units

Answer 24

mass per volume

mg of ethanol / cm3 of blood

Question 25

what is the overall reaction of the oxidation in the alcosensor

Answer 25

ethanol oxidised to ethanoic acid and water C2H5OH + O2 --> CH3COOH + H2O

Question 26

account for differences in solubilities of organic molecules in different solvents

Answer 26

polar organic compounds dissolve in WATER by HYDROGEN bonding non polar organic molecules dissolve in ORGANIC solvents (eg hexane, benzene) thru LONDON forces

Question 27

why does solvenet extraction work

Answer 27

uses the fact that a solute may show the greatest differece between 2 immicisble solvents (Extraction = choosing a solvent which selectively dissolves a particular component)

Question 28

what is partition (in solvent extraction)

Answer 28

when a solute is given the chance to dissolve in both immiscible solvents, solute becomes unequally distributed

Question 29

4 steps solvent extraction

Answer 29

1 product mixture is aq sol, contains desired product X (which has high sol in hexane than in water) 2 mixture added to seperating funnel, vol of hexane added + shaken + left to settle = hexane upper layer bc less dense than water 3 X dissolved more in hexane -- lower layer drained away = leaves hexane layer w high amt of dissolved X 4. evap of hexane = X recovered

Question 30

how is solvent extraction used in preperation of penicillin

Answer 30

penicillin is extracted from aq solution using trichloromethane as a solvent

Question 31

drug isolation and purification can be caried out using differences in? 2

Answer 31

volatility and solubilities in diff solvents

Question 32

2 concepts that differences in volatility uses

Answer 32

molecular size: incr size = decr volatility bc incr london forces polarity: more polar functional grps = decr polarity bc incr abiltiy to form h bonds or dd interactions

Question 33

why does fractional distillation work

Answer 33

exploits differences in volatility - concepet of evaporation and condensation as the simple distillation process

Question 34

what are fractions in fractional distillation

Answer 34

contain a mixture of liquids whihc boil within a narrow temperature range

Question 35

2 processes where fractional distillation is used

Answer 35

isolation of drug products from liquid mixtures seperation of chemical feedstock

Question 36

what does Raoult's Law state

Answer 36

that the VAPOUR PRESSURE of a volatile substance in a SOLUTION = vapour pressure of PURE subtance MULTIPLIED by MOLE FRACTION in solution

Question 37

what is vapour pressure

Answer 37

pressure exterted by a vapour in equilibiurm with its liquid at a given temp in a closed system

Question 38

what is mole fraction

Answer 38

the fraction of moles of the substance in a mixture mole fraction = moles of solute / total moles of solution

Question 39

when does raoult's law only apply?

Answer 39

ideal solutions -- those containing fully miscible liquids

Question 40

how to calculate total vapour pressure of a solution

Answer 40

= sum of component vapour mixtures

Question 41

how to calculate vapour pressure in mixture

Answer 41

= mole fraction of A x vapour pressure of pure A