test 1 Flashcards

1
Q

measurement

A

a trial, replicate (specific)

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2
Q

determination

A

several trials (1 analyte) (general)

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3
Q

analysis

A

several analytes [ie blood panel]

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4
Q

technique

A

many times [with] a particular instrument

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5
Q

method

A

a way to determine an analyte using a particular technique

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6
Q

procedure

A

set of instructions that can be modified if needed

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7
Q

protocol

A

a specific set of instructions

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8
Q

What are the 10 Figures of Merit ?

A
  1. Accuracy
  2. Precision
  3. Sesitivity
  4. LOD (Limit of Detection)
  5. Linear Dynamic Range
  6. Robust/ Rugged
  7. Analysis time
  8. Selectivity
  9. Cost
  10. Sample size
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9
Q

sensitivity*

A

response vs concentration plot

the measure of the ability to establish that such differences are significant

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10
Q

LOD

A

Limit of Detection- the smallest amount of analyte that can be determined with confidence
-the minimum amount of analyte ( concen. or mass) that is “significantly different from the blank”

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11
Q

linear dynamic range

A

number of #s of orders of linearity of your calibration

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12
Q

robust/rugged

A

ability to minimize down-time

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13
Q

selectivity

A

the ability of the method to distinguish the analyte from the concomitants (forest) (needle in a haystack)

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14
Q

sample size

A

amount of sample one has to work with

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15
Q

Constituent Concentrations in a Sample (4)

A

1) major- 1-100%
2) minor- 10ppt-100ppm
3) trace- 100ppm-1ppb
4) ultratrace- = 1 ppb

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16
Q

Overall Sample Size (4)

A

1) macro- 100mg and up
2) meso/semi micro- 10-100mg
3) micro- 0.1-10mg
4) ultramicro-

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17
Q

replicates

A

(N) # of trials simulating the same conditions

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18
Q

mean (x-bar) (mu)

A

x-bar= (Sum of replicates)/ N

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19
Q

median

A

middle data point in rank order

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20
Q

4 Descriptors of Precision

A
1- range
2- standard deviation
     --> relative standard deviation
3- coefficient of variation (CV)
4- variance (s^2)
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21
Q

2 Descriptors of Accuracy

A

1- absolute error (E)

2- relative error

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22
Q

absolute error*

A
  • descriptor of accuracy
  • E = xi - xtrue
  • shown with sign dependence
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23
Q

relative error*

A
  • descriptor of accuracy

- %Er ={(| xi - xtrue |)/ xtrue}x 100

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24
Q

Types of Error

A

1- Systematic

2-Indeterminate

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25
Q

systematic error*

A
  • type of error
  • determinant
  • can be corrected/avoided/minimized
  • can be constant/ variable
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26
Q

constant systematic error** (EX)

A

ie. balance bias

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27
Q

variable systematic error** (EX)

A

ie. burret with varying diameter

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28
Q

3 Sources of Error

A

1- Instrument– any measuring device
2- Method– hardest to correct;
-ie. kinetics of method, degradation of product
3-Personal– its personal!
-ie. colorblindness, shakiness

29
Q

SRM

A

Standard Reference Mixture

30
Q

4 Types of Analysis

A

1- Qualitative
2-Quantitative
3- Characterization
4- Fundamentals

31
Q

Qualitative Analysis*

A

What kinds of things are in your sample…

32
Q

Quantitative Analysis*

A

How much of a particular analyte is in your sample…

33
Q

Analytical Process [Scientific Method]

A
  1. Defining the problem
  2. Selecting the method of analysis: Cost VS Precision
  3. Handling the sample
    • Where to obtain
    • How to sample
    • # of replicates
    • # of dilutions
  4. Performing the required separations—isolate analyte
    a. Interferences – another compound that adds or subtracts from the signal
    b. Matrix—all constituents in a sample
    - -rocks/ gold example
  5. Performing the measurement= assay (obtaining the purity)
  6. Data presentation
  7. Check for anomalies
34
Q

Methods of Analysis

A

1) Volumetric
2) Gravimetric
3) Spectroscopic

35
Q

Volumetric method of analysis*

A

measure a well-known volume of substance that relates directly to your analyte

36
Q

Gravimetric method of analysis*

A

determine the mass of ones analyte or derivative…

37
Q

Spectroscopic method of analysis*

A

determine the analyte concentration after measuring the amount of interaction of light with matter

38
Q

Concentration: Solid Analyte in Soluble Mixture

A
(gram analyte)/ (gram sample) x 100/1000/1000000...
(pph) aka w/w% 
(ppt)
(ppm)
(ppb)
39
Q

Concentration: Solid in Liquid Matrix

A

1 ppm = 1mg/L

40
Q

Concentration: Liquid in Liquid

A

(w/v)% = (gram analyte/1,0mL sample)x 100

41
Q

Molarity

A

M= mol/L

42
Q

Normality

A
  • N= equivalents analyte/ L solution

- N= (# reacting units)/(#moles)(L soln)

43
Q

Equivalents =

A

= (#moles)/(#reacting units)

44
Q

Equivalent weight

A

Formula weight/ # equivalents

45
Q

Analytical Molarity

A

-does not consider the state of the solution

CHA = (#moles analyte)/(L soln)

46
Q

Species Molarity

A

-molarity of one component in solution “[ ]”

47
Q

p- function

A

p(anything)= -log(anything)

48
Q

titration

A

procedure in which a known substance (titrant) is carefully added to a (titrand) analyte until the reaction is complete

49
Q

titrant

A

known substance`

50
Q

titrand

A

unknown concentration analyte

51
Q

endpoint

A

where the titration ceases

52
Q

equivalence point

A

equal # moles of analyte and titrant

53
Q

titration error

A

the “distance” between the equivalence point and the end point

54
Q

How do you minimize titration error?

A

run a blank

55
Q

2 Titration Styles

A

1- direct – add titrant to endpoint

2-back– pass equivalence point on purpose, then add second titrant

56
Q

5 1/2 Elements of a Successful Titration

A
  1. Rxn has to be Stoichiometric
  2. Rxn should be rapid
  3. No side rxns
    3 1/2. no interferences
  4. There must be a sharp change in solution property @ endpoint ie indicator
  5. You want the rxn to be quantitative
57
Q

standard solution

A

a solution in which the concentration is very well known

58
Q

Primary Standard Requirements:

A

The primary standard should be…

  1. pure
  2. stable to drying
  3. readily available
  4. best to have a high formula weight
  5. soluble
59
Q

4 Classifications of Volumetric Methods:

A

1-Acid/Base
2-Redox– oxidizing agent and reducing agent
3-Complexometric– soluble analyte with color
-ie EDTA
4-Precipitation– endpoint is the persistence of a solid

60
Q

Basic Equipment:

A
  • analytical balance
  • Buret
  • volumetric flask
  • volumetric pipet
    • transfer pipet (glass)
    • micropipet
61
Q

tolerance

A

the allowable error associated with a device

62
Q

indeterminate error*

A

accidental…

these errors are determined by making successive measurements (by the same analyst) using the same method

63
Q

uncertainty

A

an expression that shows the range of values that are all possible for your determination (tolerance)

64
Q

propagation of error: 1- addition/subtraction

A

s = [S(1)^2 + S(2)^2 +S(3)^2 + S(4)^2]^1/2

65
Q

propagation of error: 2- multiplication/ division

A

s/y =

66
Q

propagation of error: exponents

A

.

67
Q

what is the difference between an analytical sample and a statistical sample?

A

analytical: sample= trial(discrete thing)
statistical: sample= the treatment of a group of data turned into sample

68
Q

population

A

set of objects to be studied

N~30