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2103 Asthma/COPD > Particle Size Analysis > Flashcards

Particle Size Analysis Flashcards

1
Q

Challenges

A
  • HETEROGENEOUS powder particle size - RANGE
  • IRREGULAR particle shapes
  • 2D
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2
Q

Solutions

A

Equivalent sphere diameter
Statistics
Analytical techniques

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3
Q

Particle shape considers

A

Convexity, aspect ratio, circularity, solidity

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4
Q

Particle size ANALYTICAL TECHNIQUES

A 
Sieving
sedimentation
microscopy
image analysis
laser diffraction
dynamic light scattering
electrozone sensing
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5
Q

LASER DIFFRACTION:

particle size range

A

0.01-3500ym

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6
Q

LASER DIFFRACTION:

mechanism

A

Particles passing through the laser beam scatter light.

ANGLE OF LIGHT SCATTER is measured by photodetectors around sample chamber
- measures LIGHT INTENSITY

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7
Q

LASER DIFFRACTION:

smaller particles have a ____ scatter angle

A

WIDER

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8
Q

LASER DIFFRACTION:

advantages

A

RAPID (mins)
minimal sample prep
NO CALIBRATION

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9
Q

DYNAMIC LIGHT SCATTERING:

particle size range

A

0.3nm-10ym

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10
Q

DYNAMIC LIGHT SCATTERING:

mechanism

A

(same as laser diffraction)
BUT
Photodetectors measure FLUCTUATIONS in scatter.

Scatter due to BROWNIAN MOTION

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11
Q

Compare LD & DL:

A

LD uses wet & dry samples (DL: wet only)
LD: broader particle size range
LD measures ANGLE OF LIGHT SCATTER
DL measures FLUCTUATIONS of light scatter

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12
Q

NORMAL DISTRIBUTION CURVE:
mean
median
mode

A

mean=median=mode

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13
Q

NORMAL DISTRIBUTION CURVE:

shows

A

UNIFORMITY of particle size

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14
Q

BIMODAL DISTRIBUTION:

relate modes & peaks

A

1 peak = 1 mode

2 peaks = 2 modes

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15
Q

BIMODAL DISTRIBUTION:

shows

A

2 or more distinct populations in powder

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16
Q

NEGATIVE SKEW:
mean
median
mode

17
Q

NEGATIVE SKEW:

shows

A

MORE LARGER PARTICLES

18
Q

NEGATIVE SKEW:

peak lies on ___ side

19
Q

POSITIVE SKEW:
mean
median
mode

A

mean>median>mode

20
Q

POSITIVE SKEW:

shows

A

MORE SMALLER particles

21
Q

POSITIVE SKEW:

peak lies to ____ side

A

LEFT

closest to y axis

22
Q

D values:

calculate

23
Q

SPAN

equation

A

(D90-D10)/D50

24
Q

SPAN shows

A

width of particle size distribution

25
Q

IQCS<0

A

NEGATIVE SKEW

26
Q

IQCS>0

A

POSITIVE SKEW

27
Q

IQCS=0

A

NORMAL DISTRIBUTION

28
Q

IQCS values lie between range …….

29
Q

IQCS shows

A

Interquartile coefficient of skewness

30
Q

POLYDISPERSITY INDEX: shows

A

uniformity of particle size

31
Q

POLYDISPERSITY INDEX:

assumes

A

NORMAL DISTRIBUTION

32
Q

POLYDISPERSITY INDEX:

equation

A

SD

mean particle size

33
Q

POLYDISPERSITY INDEX:

MONODISPERSE

A

narrow dist, uniform particle size

34
Q

POLYDISPERSITY INDEX:

POLYDISPERSE

A

broad dist

variable particle size

35
Q

DYNAMIC LIGHT SCATTERING:

which equation relates?

A

Stokes-Einstein Equation

2103 Asthma/COPD (8 decks)

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