Page 52 - BR20828_E Accucore 0713S

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Compound
Peak Width Resolution Signal-to-Noise Ratio
Accucore XL Fully Porous Accucore XL Fully Porous Accucore XL Fully Porous
Simazine 0.108 0.151 N/A N/A 3453 1468
Simetryn 0.106 0.151 16.42 11.75 14790 6109
Atrazine 0.112 0.160 3.31 2.13 4828 2027
Prometon 0.112 0.153 4.30 3.61 3603 1534
Ametryn 0.111 0.158 11.56 7.49 16170 6718
Propazine 0.114 0.163 2.95 1.92 5745 2390
Prometryn 0.115 0.162 14.64 9.98 12363 5200
Figure 3: Signal-to-noise ratio comparison for the triazines gradient method in Figure 2, showing improvements
between 135% and 142% for the 7 triazines
Table 2: Peak width, resolution, and signal-to-noise ratio data for seven triazines
Signal-to-noise ratio
Simazine
2000
0
4000
6000
8000
10000
12000
14000
16000
Simetryn Atrazine Prometon Ametryn Propazine Prometryn
18000
Fully porous 5 μm Accucore XL 4 μm
Sensitivity comparison in trace analysis
In trace analysis, the analyst is challenged to achieve the lowest possible limit of detection (LOD),
the lowest concentration that can be detected, and the limit of quantification (LOQ), the lowest
concentration that can be reliably quantified at a given signal-to-noise. For example, LOD is
typically defined as the concentration on column that gives S/N = 3 and LOQ where S/N = 10. To
achieve this goal, it is important to select the chromatographic parameters that will maximize Cmax,
namely high efficiency columns that produce symmetrical peaks, and which are not excessively
retained.
In Figure 4, a comparison is made of the signal-to-noise ratios obtained for a series of triazines at
trace level (1 ng injected on column) separated on Accucore XL 4 µm and fully porous 3 and 5 µm
columns. It can be seen that the higher efficiency of the chromatographic peaks on the Accucore XL
HPLC column enables greater signal-to-noise ratios, which are on average 116% and 100% higher
than those obtained on fully porous 5 and 3 µm columns, respectively. The derived LODs and
LOQs (based on this data) are listed on Table 3.
Column LOD (ng) S/N = 3 LOQ (ng) S/N = 10
Fully porous 5 μm 0.6 2.0
Fully porous 3 μm 0.6 1.9
Accucore XL 4μm 0.3 0.9
Table 3: Derived LODs and LOQs