I have used the 8800 for the past 3 years and have recently demo'd the 8900. From my notes:
1. The 8900 has a new skimmer cone design (same as the 7900) and extraction lens set design (similar to the 's' style - extract 1 is more of a cone shape)
2. The 8900 has a new lens inside the collision cell called axial acceleration lens. Agilent wasn't forthcoming with the principal or design behind this but I'll give my best guess: In the 8800 ions in the reaction cell were non-thermal meaning they still had significant kinetic energy in the axial direction. The ions essentially moved too fast through the cell and a large proportion did not react with reaction gases when the gas did not have a permanent dipole moment (e.g. O2). In the new design, the axial acceleration (in my view should be called axial deceleration) increases the ion residence time in the cell and has better reaction efficiency (see As and Se below). Bi-molecular cross sections are strongly dependent on ion kinetic energy so the best reaction cells have thermalized ion beams: slow ions, long reaction times, easily predictable reaction chemistry. The axial acceleration is user-controlled in the tune window.
3. S analysis - the 8900 has an option to purify the incoming argon. It's a packed gas sieve. This lowered the background at m/z 48 significantly compared to our 8800.
4. P analysis - sorry, I didn't test this
5. As and Se analysis - again, the axial acceleration helped. On our 8800, in O2 mode, we usually get ~40,000cps/ppb for As (as AsO). On the 8900 with axial acceleration off, we measured sensitivity 67,000 cps/ppb. With 1.5V axial acceleration, sensitivity was 120,000 cps/ppb for As. In comparison, the KED mode sensitivity for As was 7,000 cps/ppb. So axial acceleration plus new interface plus new extraction lens increased the AsO sensitivity in O2 mode by 300%. We measured less improvement for 78Se (KED 560 cps/ppb, O2 no axial field 2000 cps/ppb, O2 axial field 2600 cps/ppb). I would guess that Se analysis improved less than As because the Se-O2 rxn is less efficient than the As-O2 rxn.
Patrick J. Gray, Ph.D., Chemist
Chemical Contaminants Branch
Center for Food Safety and Applied Nutrition
Food and Drug Administration
5001 Campus Drive College Park Md 20740-3835
Office: (240) 402-5026
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From: PLASMACHEM-L: Analytical Chem.(ICP's, DCP's, MIP's). [mailto:[log in to unmask]] On Behalf Of Lyndon Palmer
Sent: Monday, March 06, 2017 9:50 PM
To: [log in to unmask]
Subject: Agilent Triple Quad ICPMS? - 8800 or new 8900
For any users of the Agilent Triple Quad, I am wondering what peoples experience has been with the Agilent Triple Quad - 8800 or new 8900 compared to the Agilent 7900?
Are there any other Triple Quad instruments or equivalent on the market as yet?
We are currently using an old Agilent 7500CX at present for plant / grain / food analysis. We are happy with the performance except for the non-analysis of S, which we would like to be able to analyse in the same run rather than on ICPOES or some other way.
We currently analyse the following elements: Al, As, B, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Se, Ti & Zn.
Expanded areas of particular interest and other questions are:
1. S analysis.
* I have read that the 7900 can analyse S - is that so and how is it done?
2. Better P analysis.
3. As and Se at quite low levels and removal of potential interferences - oxides and doubly charged species.
4. Does the Triple Quad reduce or get around the oxide interferences on elements e.g. MoO and Cd etc.
Mr. Lyndon Palmer
Flinders University Plant Nutrition
School of Biological Sciences
Carpark7, Room 201
South Australia, AUSTRALIA 5042
Tel. +61 8 8201 3536
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