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In general, the Peek Mira Mist is the correct nebulizer.|
The Peek Mira Mist handles most liquids, most flow ranges used in ICP and ICP/MS, and is the most rugged, longest life of our nebulizers due to its outer body being strong PEEK material. However, for some cases you should choose one of our other nebulizers. The following may help you select which one, and if the quick list does not help, the more detailed tables following may help.
1. PEEK Mira Mist:
The most common choice for most Instruments, most samples: It has a lower cost than the Teflon Mira Mist, same excellent stability, %RSD, intensities. Can run from 0.25 to 2.5 ml/min. The Peek body will not handle some organic solvents, HF over 5%, high concentrations of HNO3 or Sulphuric acid.
2. Teflon Mira Mist:
The most versatile nebulizer for any instrument running concentrated acids, HF, or organic solvents. It also runs low acids or waters of course - it handles all solvents. Its excellent stability, low %RSD, and high intensities are the same as the Peek Mira Mist. The main reason to choose it is for sample acids/solvents that would damage the Peek bodies.
3. Ari Mist:
For low flow applications for ICP/MS instruments. Handles small particulates - at 225 micron ID, the sample capillary is still larger than most concentrics. Runs from 50 ul/min to 1.5 ml/min. The Peek body will not handle some organic solvents, HF, high concentrations of HNO3 or Sulphuric acid. Excellent stability, %RSD, intensities.
Best choice for lots of undissolved particles, or slurries. Gives the same intensities and stability as a Mira Mist for more than 0.5 ml/min sample flows. Good for most Instruments, most samples, with concentrated acids, or organic solvents and lot of undissolved particles, very good stability, %RSD, intensities.
Generally, the T2100 is a better choice for any application considering these. These are usually only selected if trying to match old procedures and protocols. The T2100 lasts longer, handles larger undissolved particles, and gives the same intensities and stability for more than 0.5 ml/min sample flows. These will work for most instruments, most samples, with concentrated acids, or organic solvents and lot of undissolved particles, very good stability, %RSD, intensities.
6. Mira Mist CE, Ari Mist HP:
These are special application high pressure nebulizers: only used when low flow or very high stability and intensities are required. Highest cost, require higher pressure than available in most instruments.
7. Enya Mist
For ICP/MS applications. Allows direct connection of uHPLC, HPLC, and syringe pumps. Handles from 200 nanoliters/min to 50 microliters/min.
Small sample capillary provides enough back pressure to enable Split Flow applications. Can split sample flow at nebulizer in 30 - 50 X splits.
8. PFA 250
For ICP/MS applications. This is essentially an Ari Mist made of PFA on the parts that are in contact with the sample. The PFA 250 allows a bit lower flow than a standard Ari Mist, but with all the advantages still present: low flow, difficult to salt or plug, hihg particulate tolerance. Handles from 25 microliters/min to 1 ml/min. PFA inner capillary extends out back of nebulizer for easy connection to 1/16" tubing fittings, and PFA only contact with the sample.
9. SS 50 & LB 30:
Special application low pressure high sample flow high gas flow nebulizer. Used for industrial sprays, not for ICP, ICP/MS analysis. These nebulizers are made to order and can be made in many sizes and shapes, with many types of materials.
NEBULIZER SELECTION CRITERIA DETAILS
DISCUSSION of SELECTION CRITERIA
Burgener Nebulizers have pressure ratings to indicate what pressure is required for 1 liter per minute Argon flow. Most Torches require .7 to .8 L/min, and flow rates above or below the torch optimum change the location of the plasma, and therefore also change the resultant intensities and stability of the plasma. The type of torch determines the optimum flow rates, not the nebulizer. The optimum pressure for the nebulizer is usually as high a pressure as your instrument will provide. But the Optimum flow rate is determined by the type of torch and rarely matches the optimum of the nebulizer itself. While optimizing nebulizer flow rates or pressures, you are optimizing the flow rates to the torch and the whole system.
The above charts list the normal Operating Pressures assuming a 0.8 liter/minute Argon flow rate.
Some torches require 1.5 L/min, some use 1 L/min and some as little as 0.6 L/min. So the operating pressure of a nebulizer depends on the torch and can not be indicated on the nebulizer package since we do not know what torch will be used with it. We mark the package to indicate a specific flow rate, and we have chosen 1 Liter / minute as a standard. A nebulizer that requires 45 psi (15 psi = 1 bar) for a flow of 1 L/min will usually be operated at .8 L/min, which requires about 35 - 37 psi. In general, for all makes and designs of nebulizers, they work better at higher pressures. Our 30 psi rated nebulizers are designed for high flow (older design) torches that require 1.5 L/min. With a 30 psi per 1 L/min nebulizer, you can operate at 45 psi for 1.5 L/min which fits instruments with a maximum of 45 psi. Most instruments use newer torch designs and require .8 L/min or less, so we rarely sell 30 psi rated nebulizers.
Nebulizers work better at higher pressures. To get the best possible sensitivities and lowest %RSD, 100 psi or more is desirable. Our Legere, Mira Mist CE and Ari Mist HP nebulizers use 70 - 125 psi for 1 L/min, which means that most torches at .8L/min will require 50 - 80 psi for the nebulizer to optimize. This requires an instrument able to deliver higher pressures, and usually means that you will need an Argon supply independent of the instrument controls. A double stage regulator on a standard Argon tank will provide stable gas flows and should last a week or more of continuos operation.
Our Ari Mist HP nebulizer is designed for 5 to 20 microliter/minute sample flows. To maximize the number of instruments easily used with it, while maintaining a high enough flow rate to sustain a mist, we designed the Ari Mist to require about 75 psi for 1 L/min gas flow. Optimizing on the PE/Sciex Elan ICP/MS, we found that a torch routinely running with 0.8 L/min actually required 1.2 L/min (85 psi) to optimize with a 5 microliter/min sample flow. The PE mass flow controller was set for 1.5 L/min, but could not provide the pressure required to accomplish that, nor did it indicate that the actual flow rate was much lower than we had set - it had no pressure indicator, just a total flow setting. We had to use a separate gas line to get the actual 85 psi. This is a problem with most mass flow controllers: they do not have any way to indicate that there is not enough gas pressure to deliver the desired flow, so you may get low or no counts due to too little gas pressure without any indication in the instrument setup that the gas pressure is the problem.
The nebulizer requires Pressure to operate, but instruments with mass flow controllers list Flow not pressure, and the torch requires a set Flow not Pressure. To know if your system is properly optimized, you need to know the pressure and the flow, and unfortunately most manufacturers do not have both parameters available.
With the above preamble, you can now follow the nebulizer selection criteria:
1. Always use the highest pressure rating possible for your machine. If your machine can provide 125 psi, use a 125 psi nebulizer for the best sensitivities and lowest %RSD.
2. Accept your machines limitations in pressure - the lower rated pressure nebulizers are acceptable for most routine analysis. Only go to higher pressures if you absolutely require the precision - the nuisance of a separate high pressure tank of Argon is not worth it if the slightly lower precision is acceptable.
3. For General usage, the Mira Mist is the best nebulizer, with the T2100 a close second.
For most ICP, the Mira Mist (Peek or Teflon versions) are the most reliable, most sensitive, most stable and easiest to use. They rarely plug or salt and their long term stability is unmatched by any other.
The Mira Mist has a large sample passage ID: 500 microns or .017 inch - 4 times the cross sectional area of standard glass concentrics. Most particles will easily pass through the nebulizer without plugging. The Mira Mist CAN plug, but it is solid so it can be cleaned with a cleaning wire - however, a cleaning wire can also easily destroy the nebulizer if it touches the gas orifice area. So to prevent plugging, use a capillary tube smaller in ID than the Mira Mist sample ID.
4. If you are running samples with slurries or high levels of undissolved particles, then the T2100 is the best choice.
In previous years, the T2002 and the TJA Trace were the recommended nebulizers. The T2002 and Trace nebulizers fit all standard chambers that can use a Meinhard, and they run all solutions without plugging or salting problems. These CAN NOT plug. The sample passage is much bigger than the capillary tube ID used to deliver the sample. The capillary tube can plug, but it is press fitted into the nebulizer and can be easily changed. The T2100 is similar, basically can not plug, has better sensitivity and stability, and it is easier to change the capillary tubing to the nebulizer. While we will continue making the T2002 and Trace nebulizers for many years, the T2100 is usually a better nebulizer.
5. For ICP/MS instruments, for Low Sample Flow use the Ari Mist and Ari Mist HP nebulizers. They differ from the Mira Mist in having smaller ID sample capillary - minimizing the sample flow rate through the nebulizer. The Ari Mist is designed to run as low as 50 ul/min and the Ari Mist HP is designed to run as low as 5 ul/min. The Ari Mist has a smaller sample passage ID: 150 microns for the Ari Mist HP and 225 microns for the Ari Mist. They CAN PLUG. Use with particle-free samples.
6. For interfacing ICP/Ms withg CE or LC, the Mira Mist CE is the choice. You can use the Mira Mist CE simply for the best high precision and low flow rates, if you have access to high pressure Argon. It will fit a cyclonic chamber, and any other standard chamber. The Mira mist CE has an ID of 500 microns or .020 inch, a bit larger than the regular Mira Mist, but it is set for high pressure Argon sources, and it is manufactured to be able to run at VERY low sample flow rates. It will handle high salts and solids, and gives excellent precision and sensitivity. It is mainly designed for an interface between CE or LC systems with an ICP/MS. While it is our best nebulizer for most applications, it is too expensive to be justified for the small improvement over the Mira Mist unless you are interfacing ICP/Ms with other instruments.
Teflon is a registered trademark of E.I. DuPont De Nemours Company and in all cases in this web page refers to PTFE (PolyTetraFluoroEthylene)