M3 ICP E
MISSION
S
PECTROSCOPY
: O
PERATIONAL
V
ARIABLES
Last Revised: March 2015
1. REAGENTS & EQUIPMENT
1.1
1000 mg/L Ca
1.2
10 mg/L Cu/Fe/K/Na/Pb/Zn mixed standard
1.3
10 mg/L Mg
1.4
White wine
2. PROCEDURE
2A. Working range
2.1
Prepare five serial 10 to 100 dilutions from 1000 mg/L.
2.2
Record the intensity of each of the Ca standards at two different wavelengths.
2B. Plasma problems
2.3
Aspirate a sample of white wine and observe what happens.
2C. Instrumental effects
2.4
Measure intensities for the 6 element standard at different:
• RF power (0.8, 1, 1.2 kW)
• pump speed (8, 15, 30 rpm)
2.5 Measure the intensity of the Mg standard at two wavelengths (280 & 285 nm) at three RF powers.
For each line in 2A & 2C, record whether it is atomic (I) or ionic (II).
3. REPORT
Calculations
• plot a graph of log (intensity) vs log (conc) for each of the two Ca lines
• normalise the readings for each set of data (e.g. RF power) and for each element separately as follows:
− divide each intensity value by the value at the lowest instrument setting
− multiply each by 100
− this should mean that the normalised value for each element at the lowest setting is 100
• plot the normalised intensities for all six lines against the instrument variable (i.e. two graphs with six lines in each)
• calculate the intensity ratio for the Mg lines (280 ÷ 285) at each power
• plot the Mg ratio vs RF power

Discussion
• estimate the linear response region for each of the Ca lines
• comment on the use of different wavelengths to suit different concentration samples
• explain the behaviour observed for the wine
• describe what instrumental settings should be adjusted to allow direct analysis of wine samples
• describe the differences in behaviour with increasing power/pump speed for the six elements in
2.4
• group the elements by similarity of behaviour
• tabulate optimum conditions (highest intensity) for the six elements
• describe the difference in the Mg intensities for the two lines in 2.5
• comment on the Mg ratio results compared to those in the GBC brochure (Reference article)
Questions
1.
Describe one other way of overcoming the problems with running wine through the ICP. What problem could be encountered using this approach?
2.
How does the GBC Integra XL (used in Reference article) compare to the instrument used in this exercise in terms:
• axial vs radial
• sequential vs simultaneous
• resolution
References (downloadable from subject webpage)
GBC Integra XL brochure
M3 p 2

2A. Working range
Ca Solution
State:
nm
M3 R ESULTS S HEET
nm
State:
0.01 mg/L
0.1
1
10
100
2B. Plasma problems
Observations
2C. Instrumental effects
Mixed elements
Power Pump
0.8
1
1.2
1
15
15
15
8
1
Wavelength
30
State
10 mg/L Mg
State:
280 nm
State:
285 nm
0.8 kW
1.0 kW
1.2 kW