6


February / March 2012 Waste Category Transport (T) Inventory (I) Motion (M) Waiting (W) Over-production (O) Over-processing (O’) Defects (D) Table 2: Lean waste categories


A review of these column limitations against our project portfolio showed why methods have been developed on a broad-spectrum of columns. For a standardised approach to be successful either more instruments have to be configured for project specific analysis or columns need to be suitable for a wider range of applications.


The next step of our evaluation was to assess new technology columns. These columns possess the same stationary phases as traditional columns but claim to have superior inertness, high sensitivity with low bleed and can be operated at high temperatures.


Improve


Evaluation of New Technology Columns The initial assessment was carried out on InertCap columns (Hichrom, Theale, UK). Stationary phases chosen for evaluation were 1 and 17 with column dimensions; 10 m, 0.1 mm i.d, 0.1 µm film thickness. Polar analytes (including alcohols and primary


Chemistry 1


RXI-5Sil MS (or equivalent)


2


RXI-5Sil MS (or equivalent)


3


RXI-17Sil MS (or equivalent)


4


RXI-5Sil MS (or equivalent)


amines) were tested for inertness, sensitivity and speed of analysis. The evaluation columns demonstrated improved peak shape for polar functional groups when compared to traditional columns. Good separation was achieved with sub-10 minute methods. However the column capacity was not sufficient to analyse typical sample concentrations.


The assessment was continued on the InertCap and RXI columns (Thames Restek, Saunderton, UK ). Stationary phases chosen for evaluation were 5 and 17 with column dimensions; 20 m, 0.18 mm i.d, 0.36 µm film thickness. Project analysis (performed on existing methods) was repeated on the evaluation columns. These columns demonstrated improved peak shape for polar compounds (even when compared to polar (1701 and 624) traditional stationary phases), the sharper peaks contributed to improved resolution of the analytes. Multiple injections were run over evenings and weekends, low bleed was observed and chromatograms were reproduced


Dimensions


20 m, 0.18 mm i.d, 0.36 µm film thickness


20 m, 0.18 mm i.d, 0.72 µm film thickness


Oven


20 m, 0.18 mm i.d, 0.36 µm film thickness


15 m, 0.25 mm i.d, 0.1 µm film thickness


Table 3: Column and method details to support the suite of standardised methods Parameters: Injector: Description Unnecessary movement between processes Production of ’non-value’ added goods Unnecessary movement of people or parts For a process to be completed Extra ordered ’just in case’ Process more than required by customer Not right 1st time, repetition of a process Implementing Solutions


The evaluation lead to the development of two methods (method parameters are listed in Table 3)


• Method A was an 8 minute method that had resolution for most applications during the evaluation. The initial temperature of 80 °C improved peak shape for polar compounds and reduced total run time by 30% (compared to the traditional starting temperature of 50°C).


• Method B was a 12 minute method that improved resolution of complex volatile (<80°C multiple component) samples.


The R&D portfolio in our organisation is broad and therefore four columns were initially selected for the standardised method suite (column details are listed in Table 3)


• Column 1 was chosen as the primary column. The parameters demonstrated good selectivity and peak shape across projects and the capacity was adequate across typical sample concentrations (project examples are shown in Figure 4)


• Column 2 improved resolution of complex volatile samples and improved peak shape for highly polar compounds (small acids).


• Column 3 (50 %-Phenyl) was chosen to complement selectivity; however with the high success rate of columns 1 and 2 there are no applications to date.


• Column 4 was chosen for thermally sensitive compounds. However increasing initial oven temperature and reducing the temperature gradient column 1 produced good chromatography whilst maintaining selectivity for compounds (an example is shown in Figure 5)


Method A


Volume: 1 µL Temperature: 250°C Split: 150:1


Carrier Gas: He at 1.0 mL/min, Constant Flow


Initial Temperature: 80°C Initial Hold: 1 min Ramp: 45°C/min Final Temperature: 300°C Final Hold: 3 min


Detector:


320°C H2:Air:N2 30:300:30 mL/min


Initial Temperature: 40°C Initial Hold: 5 min Ramp: 45°C/min Final Temperature: 300°C Final Hold: 3 min


Method B


throughout the evaluation to demonstrate robustness.


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