Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

FAD > Quantitation > Flashcards

Quantitation Flashcards

1
Q

Why use quantitative data?

A
  • clinical chemistry
  • urine and plasma drug conc
  • biomarkers (can predict when patient has an episode in sickle cell anaemia)
  • drug toxicity (trace metals in the blood)
  • drug pharmacokinetics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Two types of quantitative methods

A
  • classical methods

- instrumental methods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are classical methods?

A
  • wet chemistry

precipitation, extraction, distillation, boiling point, melting point, gravimetric and volumetric analysis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are instrumental methods?

A

analytical measurement

conductivity, electrode potential, light absorption or emission, mass to charge ratio. fluorescence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How to determine the concentration in a sample?

A

use the peak area

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Does it need to be a known compound

A

yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

matrix?

A

establishment of the method of analysis of drug in the matrix

analyse standard containing a known amount of drug in the matrix/ surrogate matrix

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

quantiation

A

compare the response of an unknown sample to the response of a known standard

data must be acquired and processed under identical conditions

requires good chromatographic resolution

response of the compound is within the linear range of the detector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what does the chromatographic peak integration define

A

an operation where the area under the peak is measured

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the integral technique and integral method for measuring peak area

A

integral technique- splits the peak into a large set of rectangles and summing their area

integral method

area= change in absorbance x change in time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is external standard quantitation?

A

For an external standard quantitation, known data from a calibration standard and unknown data from the sample are combined to generate a quantitative report.

It is called external standard because the standard or known material is separate or external to the unknown material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

equation for the response factor?

A

response factor= area/ concentration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Problems with external standard quantiation

A

cannot draw a line with just one point

cannot have a 1 point/2 point calibration

need an 8 pint calibration curve

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

how is a calibration curve made

A

by analysis of standard solutions of known concentration

and measuring their peak area

best fit regression line is used to join the points

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is a better method to quantify the concentration

A

internal standard ISTD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

requirements of an ISTD

A
  • should be as similar as possible to the analyte
  • chemically and physically similar to the analyte
  • unreactive
  • pure
  • elute near the analse but well resolved
17
Q

how is an ISTD added

A

prepare a set of standards with different pg/ml

add a known quantity of the ISTD to each sample

add the same quantity of the ISTD to the test samples

analyse all the samples

18
Q

how does a internal standard calibration curve work

A
  • internal standard is added to each sample or standard in equal concentrations
  • peak area ratio and concentration ratio is plotted for each standard
  • concentration ratio of the sample s extrapolated from the peak area ratio obtained for the sample
  • concentration of the sample can be calculated as the concentration of the internal standard C(is)
19
Q

characteristics that should be considered in the validation of an analytical method

A
  • linearity
  • range
  • accuracy
  • precision
  • recovery
  • specificity
  • limit of quantitation
  • robustness
20
Q

what is linearity

A

indicates the ability to produce results that are directly proportional to the concentration of the analyse

samples prepared in a biological/ surrogate matrix in which the analytes concentration span the claimed range of procedure

samples are extracted and analysed

min of 5 concentrations should be used in 6 replicated

21
Q

what is range

A

an expression of the lower and highest levels of analyse that has been demonstrated to be determinable for the product

range is derived from the linearity study

22
Q

what is accuracy

A

the degree of agreement of the test result with the true value

the closeness of the result obtained by the procedure to the true value

23
Q

how are accuracy measurements carried out

A

on spiked samples of the matrix or surrogate matrix

at 3 concentrations within day, between day for 3 separate days in 6 replicates

24
Q

equation for % error

A

%error= (actual - experimental)/ actual * 100

low QC- 6 replicates,3 separate days
mid QC- within day
high QC- between day

%error must be less than 15%

25
Q

what is precision

A

the degree of agreement among individual results

26
Q

how should precision be measured

A
  • at 3 concentrations with 6 replicated within day and between day

complete procedure should be applied repeatedly to separate, identical samples drawn from the same homogenous batch of material

should be measured by the scatter of individual results from the mean and expressed as the relative standard deviation RSD or coefficient variation CV

27
Q

equation for coefficient variation

A

CV= (standard deviation/ mean) * 100

precision <15%

28
Q

what is specificity

A

the ability to measure unequivocally the desired analyse in the presence of excipients and impurities and may be expected to be present

an investigation of specificity should be conducted during validation of identification tests, determination of impurities and assay

29
Q

detection limit

A

smallest quantity of n analyse that can be detected and not necessarily determined in a quantitative manner

approaches:
visual evaluation
signal to noise ratio
standard deviation of the response and the slope
calibration curve
30
Q

what is limit of quantitation

A

lowest concentration of analyte in sample that may be determined with acceptable accuracy and precision

31
Q

% recovery

A

recovery = (standard/ no standard) * 100

FAD (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions