D9 drug detection and analysis Flashcards

1
Q

what are steroids

A

lipids w 4 fused rings in structure – steriodal backbone

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2
Q

2 examples of steriods
T-
C-

A

testosterone
cholesterol

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3
Q

what is testosterone

A

male steroid hormones, performance enhancing drugs

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4
Q

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

A

gas chromatography

mass spectrometry

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5
Q

what does mass spec do vs gas chromatography

A

mass spec: identifies and quantifies the components

gas chromatography: seperates chemical mixture into pure chemicals

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6
Q

3 steps for mass spectromatry

A
  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
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7
Q

what does gas chromatography do

A

seperates the chemical MIXTURE into PURE chemicals

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8
Q

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

A

the components have different affinities for the stationary and mobile phase

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9
Q

stationary vs mobile phase

A

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

mobile: inert carrier gas eg helium

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10
Q

describe how gas chromatograpy works

A

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)

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11
Q

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

A

boiling point and solubility

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

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12
Q

why is the temperature in the column controlled in gas chromatography

A

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

  • changing temp controls retention times = changes amt of seperation
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13
Q

what is retention time in terms of gas chromatography

A

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

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14
Q

name the 3 methods for organic structure analysis and identification

A

mass spectroscopy
infrared spectroscopy
proton NMR

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15
Q

what is ethanol is breath

A

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

C2H5OH (aq) <=> C2H5OH (g)

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16
Q

what instruments are used to measure ethanol conc in breath

A

breathalysers

alcosensor

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17
Q

what type of reactions happen in breathalysers

A

redox

18
Q

what ions and reaction causes the colour change in breathalysers

A

ethanol oxidised by potassium dichromate (VI)

potassium dichromate (VI) reduced to chromate (III)

orange (VI) to green (III)
6 –> 3

19
Q

steps for breathalyser

A
  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
20
Q

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

A

intoximeters

21
Q

what is an alcosensor

A

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

22
Q

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

A

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

23
Q

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

A

blood alcohol concentration

24
Q

what is blood alcohol concentrations units

A

mass per volume

mg of ethanol / cm3 of blood

25
Q

what is the overall reaction of the oxidation in the alcosensor

A

ethanol oxidised to ethanoic acid and water

C2H5OH + O2 –> CH3COOH + H2O

26
Q

account for differences in solubilities of organic molecules in different solvents

A

polar organic compounds dissolve in WATER by HYDROGEN bonding

non polar organic molecules dissolve in ORGANIC solvents (eg hexane, benzene) thru LONDON forces

27
Q

why does solvenet extraction work

A

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)

28
Q

what is partition (in solvent extraction)

A

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

29
Q

4 steps solvent extraction

A

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

  1. evap of hexane = X recovered
30
Q

how is solvent extraction used in preperation of penicillin

A

penicillin is extracted from aq solution using trichloromethane as a solvent

31
Q

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

A

volatility and solubilities in diff solvents

32
Q

2 concepts that differences in volatility uses

A

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

33
Q

why does fractional distillation work

A

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

34
Q

what are fractions in fractional distillation

A

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

35
Q

2 processes where fractional distillation is used

A

isolation of drug products from liquid mixtures

seperation of chemical feedstock

36
Q

what does Raoult’s Law state

A

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

37
Q

what is vapour pressure

A

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

38
Q

what is mole fraction

A

the fraction of moles of the substance in a mixture

mole fraction = moles of solute / total moles of solution

39
Q

when does raoult’s law only apply?

A

ideal solutions – those containing fully miscible liquids

40
Q

how to calculate total vapour pressure of a solution

A

= sum of component vapour mixtures

41
Q

how to calculate vapour pressure in mixture

A

= mole fraction of A x vapour pressure of pure A