NEWS
Results
A summary of the method time per sample with and without the
Niagara-CM Rapid Rinse is shown in Table 3. The addition of the
Niagara allowed Inorganic Ventures to reduce their certification
analysis by 71sec per sample, roughly a 35% improvement.
This reduction in time allows Inorganic Ventures to run an additional
10 samples per hour with the Niagara. The performance of the ICP
certification analysis with the Niagara is also optimal. The stability
and precision achieved certifying a 10ppm Sm CRM with the
Niagara is summarized in Figure 6. With the Niagara, an average
RSD of less than 0.5% is maintained with both Glass Expansion
sample introduction systems.
Table 3. Method timing with and without the Niagara Rapid Rinse
Without Niagara With Niagara
Total Time (sec) 200 129
Improvement N/A 35%
Samples per hour 18 28
Figure 6. Single CRM Analysis with and without NRR
Figure 6. Single CRM Analysis with and without Niagara
Corrected Intensity (counts)
0.57 %RSD
0.38 %RSD
0.50 %RSD
Sm 442.434 nm - 10 ppm Sm
Without Niagara (DuraMist/Tracey TFE)
With Niagara (DuraMist/Tracey TFE)
With Niagara (SeaSpray/Twister)
Sm 442.434 nm – 10 ppm Sm
Without NRR (DuraMist/PTFE Tracey)
With NRR (DuraMist/PTFE Tracey)
With NRR (SeaSpray/Twister)
In addition to reducing sample to sample time, the Niagara also
improves washout. To evaluate the performance of the new post
wash command of the NRRV2 software, we compared the washout
time achieved when adding a series of bubbles behind the sample
to no bubbles. Thallium (Tl) is known to be a very “sticky” element
that can result in the need for very long wash times. Thus a
1000ppm Tl solution was chosen for this test. These experiments
were carried out using an Agilent MP-AES 4100. Results in Table
4 contain values in ppm Tl for three consecutive 2% HNO3 Blank
solutions that were run after a 1000ppm Tl solution. The washout
experiments were run three ways; without the Niagara, with a
standard Niagara setup (no bubbles), and with the Niagara utilizing
the new wash command adding a series of bubbles. With the new
wash command, a dual rinse can be used in addition to adding
a series of air bubbles. The dual rinse option provides the ICP
analyst an option to use a more aggressive solution to rinse the
uptake lines, but be directed to waste and not introduced to the ICP.
sample is directed to waste while the rinse solution is directed to
the nebulizer at the analysis speed. This helps to maintain plasma
stability while reducing the uptake delay time, stabilization time and
sample load on the plasma. The Method Wizard also calculates
the appropriate size “rinse” peristaltic pump tubing to select.
This way when the Fast Pump option is used during the uptake, you
are able to maintain a constant flow to the plasma. With the Arcos
software, a minimum 1 second method rinse is required to properly
trigger the Niagara actuator. A longer post rinse time can be used
if necessary.
Figure 5. Niagara CM Rapid Rinse
Table 2. Method settings with and without the Niagara Rapid Rinse
Without Niagara With Niagara
Autosampler Probe ID 0.5mm 0.5mm
Sample peristaltic
pump tubing Orange/Green, 0.38mm ID Orange/Yellow, 0.51mm ID
Rinse peristaltic pump
tubing N/A Orange/Blue, 0.25mm ID
Waste peristaltic pump
tubing White/White, 1.02mm ID White/White, 1.02mm ID
Uptake Delay (sec) 50 23
Flush Pump Speed 45 rpm 70 rpm
Stabilization (sec) 30 15
Stabilization Pump
Speed 45 rpm 20 rpm
Analysis Pump Speed 45 rpm 20 rpm
Read (sec) 90 90
Rinse (sec) 30 1
www.geicp.com Glass Expansion Newsletter | Issue 40 4
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