The sample throughput depends on the mode of operation and on
the sample volume used for the analyte determination. The time required
for the preconcentration of 5mL ofwater sample at 3.0mLmin−1
using an elution flow rate of 6.6mLmin−1was ~4min (includingwashing
and pre-conditioning times) resulting in a sample throughput of 15
samples per hour. This is more than satisfactory even for routine
analysis.
Dynamic sorption capacity is an important parameter to evaluate
and it was determined for each substrate by integrating the breakthrough
curve. The results showed high values for both substrates:
343 mg Sb g−1 NPC and 559mg Sb g−1 pro-MWCNTs. In consequence,
high preconcentration factors (PFs) of 258 (NPC) and 420 (pro-
MWCNTs) for a sample volume of 50 mL was obtained with respect to
the Sb determination by FI-HG-AAS without preconcentration (changing
the microcolumn by other unfilled).
Trueness test for the entire analytical procedure was performed by
means of the Standard Reference Material (SRM) NIST 1643e (Trace elements
inwater). The standard addition techniquewas adopted for calibration
by adding dilute solutions of Sb(III) to the analytical solutions
(three replicates). Results were in good agreement with the certified
values as follows: 58.30 ± 0.61 μg Sb L−1 (certified) vs 56.8 ±
1.50 μg Sb L−1 (found) according to the t-test for a confidence level of
95%.