NEWS
To improve washout, it is well known that adding a bubble or series
of bubbles can help “scrub” the uptake line. However, air bubbles
introduced into the plasma can lead to instability and require longer
stabilization delay times. With the Niagara, we can easily add a
series of air bubbles with our new post wash command without
the worry of introducing any air or extra argon into the plasma.
To achieve this, the NRRV2 software sends the autosampler probe
to the rinse station after the TIS has completed, followed by a
series of commands to slowly raise and lower the probe in the rinse
station. This creates a series of air gaps between the rinse solution
(Figure 3c) helping to rinse the probe, uptake tubing and sample
peristaltic pump tubing. Once the ICP method rinse begins, the air
bubbles and any excess sample are directed to waste while rinse
solution is directed to the nebulizer (Figure 3d).
Figure 3c. Niagara CM Rapid Rinse – After TIS
Niagara in Home position
after TIS at the end of
Rrad Time
Autosampler
Probe in
Sample Tube
Internal
Standard
Rinse Waste
Figure 3d. Niagara CM Rapid Rinse – During ICP Method Rinse (post-acquisition)
Niagara in Rinse position
during Instrument rinse
Autosampler
Probe in
Wash Station
Internal
Standard
Rinse Waste
Experimental
The speed and performance of Inorganic Venture’s single element
CRM ICP-OES certification analysis was compared with and without
the use of the Niagara. For these certification experiments a Spectro
Arcos EOP (Axial) ICP-OES instrument was used in combination
with two sample introduction systems from Glass Expansion.
For samples without HF, the SeaSpray DC nebulizer was used
with the Twister spray chamber and a single piece quartz torch
(Figure 4a). The HF-resistant package consisted of the DuraMist
DC nebulizer, Tracey TFE spray chamber and fully ceramic D-Torch
(Figure 4b). The instrument parameters for the Arcos are listed in
Table 1. These particular sample introduction components and ICP
operating conditions were previously optimized.3
Table 1. Instrument parameters for Spectro Arcos EOP ICP-OES
“Glass Setup” “Inert Setup” (with HF)
RF Power (W) 1400 1400
Plasma gas
flow (L/min) 15 15
Auxiliary gas
flow (L/min) 1.0 1.0
Nebulizer gas
flow (L/min) 0.75 0.75
Nebulizer flow
rate (mL/min) 0.54 0.54
Torch Single Piece Quartz Torch
(P/N 30-808-0317)
Ceramic D-Torch
(P/N 30-808-3371 &
P/N 31-808-3425)
Injector i.d. (mm) 2.5 2.4
(P/N 31-808-3388)
Nebulizer SeaSpray DC
(P/N A21-07-USS2)
DuraMist DC
(P/N A21-07-DM1)
Spray Chamber Twister
(P/N 20-809-9199HE)
Tracey TFE
(P/N 20-809-2506)
Transfer Tube 31-808-3244 21-809-3298
Figure 4. Glass Expansion Sample Introduction systems for Arcos EOP ICP-OES
Figure 4a
Aqueous sample introduction system,
SeaSpray DC Nebulizer, Twister spray
chamber, glass elbow and single piece quartz
torch for Spectro Arcos EOP ICP-OES. Also
required is mounting bracket for Niagara Rapid
Rinse.
Figure 4b
HF-resistant sample introduction system,
DuraMist DC Nebulizer, Tracey TFE spray
chamber, PuraFlex transfer tube, and fully
ceramic D-Torch for Spectro Arcos EOP ICP-OES.
Also required is mounting bracket for Niagara
Rapid Rinse.
The Niagara package (Figure 5), consists of an electronically
controlled switching valve, dedicated control module and tubing kit.
For maximum chemical resistance the 4-port valve is made entirely
of Teflon and PEEK. An additional mounting bracket for the Arcos
EOP ICP-OES was required to position the Niagara valve next to
the nebulizer; this helps to reduce stabilization time. Please visit
www.geicp.com/intro/niagara to find the recommended Niagara
setup for your ICP.
The method timings for the Niagara CM Rapid Rinse were calculated
using the newly developed Method Wizard. These conditions
are listed in Table 2, comparing the timings with and without the
Niagara. Typically a very high “Fast Pump” would not be recommend
due to the large amount of sample introduced into the nebulizer
and plasma. However, with the Niagara the higher uptake rate of
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