The following examples go through some of the basic parts of the software to give some basic software training.
The following method allows almost complete digestion of soils and sediments:
Mix the sample thoroughly to get homogeneity. For each sample, weigh about a 0.1 g portion of the sample and transfer to a digestion vessel. Add 0.7 mL of concentrated HNO3 and 1 mL of deionized water. Digest the sample for 60 min. at 600 W by microwave heating. After cooling, add 0.3 mL of HF and digest the sample for 60 min. at 600 W by microwave heating. After cooling, dilute to 100 mL with deionized water.
Normally as a first step, semiquantitative analysis is recommended to give the approximate concentrations of analytes -this is useful to make standard solutions for the calibration curve.
Measurement m/z number --- all
Peak pattern --- Semi Quant (6 points/mass) to check for spectral interferences
Integration time --- 0.05 sec
Repetition --- 1
The following items can also be selected in SemiQuant.
Only the highest point of the 6 points is used for semiquantitative analysis. Therefore the counts in Tabulate/mass and those in the semiquantitative report will be different.
Solutions --- pure water, sample, sample + STD 1, and sample + STD 2 (Select the appropriate concentrations for STD 1 and 2 based on the semiquant results)
Analytes --- V, Cr, Co, Ni, Cu, Zn, As, Cd, Sb, and Pb
Measurement mass number and integration time ---Select as appropriate
Peak Pattern --- Full Quant (3 points/mass)
Repetition --- 3
Refer to Calibration pane and Calibration Parameters Table.
None needed (already acidified)
Create a sequence using the ASX-500 Series Autosampler.
Standard solutions --- blank, 10, 50 and 100 ppb mixed solution
Analytes --- Al, V, Cr, Mn, Co, Ni, Cu, Zn, As, Cd, and Pb
Internal standard elements --- Sc (for Al, V, Cr, Mn, Co, Ni, Cu, Zn and As), In (for Cd) and Ho (for Pb)
Set the acquisition parameters as follows:
Measurement mass number and integration time ---Select as appropriate
Peak Pattern --- Full Quant (3 points/mass)
Repetition --- 3
Using both interference equations and internal standard correction, at first raw counts are corrected by the interference equation, and then the internal standard correction is performed. Therefore, ISTD selection for masses used in the interference equation (the masses in parentheses) is not necessary in the calibration table.
Remember, background subtraction subtracts the raw data, before ISTD correction, so it cannot be used for quantitation, since it would subtract the ISTD counts from the sample. Always use blank subtraction for subtracting a reagent blank during quantitation. This method only makes the subtraction after the ISTD correction has been applied to both blank and sample.
Since ICP-MSICP-QQQ allows ppt or sub-ppt level elemental analysis, it has been commonly used in the semiconductor industry to determine ultra trace levels of impurities in chemicals and semiconductor devices. In this section, the analysis of semiconductor samples is described.
In semiconductor devices, contamination deteriorates performance: alkali and alkali-earth elements reduce breakdown voltage, transition metals reduce the lifetime of the carrier causing higher dark current, doping elements cause a shift in the device operating point and particles cause short circuits. Therefore, this contamination has to be controlled in the semiconductor industry. However, these contaminants exist everywhere in the atmosphere and special attention has to be paid to prevent airborne contamination of the various chemical and semiconductor device samples to be analyzed by ICP-MSICP-QQQ. The best way to avoid such contamination is to install the ICP-MSICP-QQQ in a clean room.
This instrument is designed for clean room use. The foreline pumps can be installed outside the clean room while the instrument itself is installed inside the clean room. All cooling air flows from outside to inside and is vented through the ventilation duct at the top of this instrument, which prevents introduction of particles from the instrument into the clean room.
The cleanliness of a clean room is expressed by its class number. Class 1000 means that the number of particles bigger than 0.5 mm is 1000 per cubic foot. The normal environment is worse than class 1,000,000. To get better cleanliness, the floor of the clean room must have a grating to allow air to flow down. Installing this instrument in a class 1000 clean room is recommended.
For the sample and standard solution preparation facility, better cleanliness will be required: a class 100 clean room with a clean draft.
This is intended as a quick start guide for liquid clinical sample preparation and analysis by this instrument. It includes "recipes" for sample dissolution and general considerations for trace clinical determination. It is not intended as an exhaustive source of information or critical sample preparation review.
Because reagent selection is at least as important as correct sampling procedures it is imperative that all reagents are of an appropriate high quality. The majority of clinical matrices can be prepared in a basic solution and we will focus mainly on these reagents. The following text lists suggested reagents and their CAS number (please check with your local laboratory reagents supplier).
Reason for use:
Main solvent & diluent base high purity essential
The most important reagent. Use Milli-Q or Elga etc Ultrapure water system (>18 MW)
Reason for use:
Basic reagent solubilises cells and stops protein precipitation
High purity or Ultra purity solution (preferred).
Reason for use:
Acts as a carbon buffer for standards and different clinical matrices improves sensitivity for high I.P. elements (As, Se)
High purity or Ultra purity solution.
Reason for use:
Complexing agent stabilizes metals in basic solution
High purity preferred. Order as the ACID (Not Na salt!)
Reason for use:
Improves sample introduction wettability and reduces likelihood of precipitation or blockage in spray chamber and torch injector
High purity preferred.
Reason for use:
Limited for clinical matrices only useful if urine samples form precipitate due to high phosphate levels. When using acidic media, all calibration and rinse solutions must be acidic in order to keep the chemistry of the sample introduction system stable. An acid concentration of 1% should be sufficient.
To prepare the diluent solution, the reagents need to be mixed in a pre-cleaned low-density polyethylene or polypropylene bottle (PFA or FEP can also be used). Mix the components as listed in the table below (with example weights assuming a final solution volume of 1 liter).
Reagent |
% in solution (w/v) |
Quantity (for 1l solution) |
|---|---|---|
1-butanol |
2% |
0.71oz |
EDTA |
0.05% |
0.02oz |
Triton X-100 |
0.05% |
0.02oz |
NH4OH |
1% |
0.35oz |
Water |
Make up to volume |
|
Mix the solution thoroughly before use.
Samples can be prepared by simple dilution - for blood, serum & plasma, a 10-fold dilution of the sample should be sufficient. For urine, use a minimum 20-fold dilution to keep the salt levels low enough to allow extended batch runs.
Sample preparation example when using the Agilent I-AS autosampler configured with the 89-position rack (6ml vials).
Pipette 0.5ml of sample (plasma, serum, blood) or 0.25ml of urine into the I-AS vial using single-use plastic pipette tips then pipette 4.5ml (plasma, serum, blood) or 4.75ml (urine) of the dilution matrix using a 5ml dispensing pipette. Pipetting the larger volume on top of the sample should give sufficient mixing, but further mixing can be done with ultrasonification, if necessary.
The volumes can be adjusted as required due to sample volume limitations. If the system is fitted with a low flow nebulizer, a full element suite can be determined with limited sample volume.
Calibrate the system with standards that are prepared in the diluent solution. All rinses should also use the diluent solution to keep the chemistry of the sample introduction system stable.