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DB-1ms
The World's #1 Phase Just Got Better!
- Virtually identical selectivity to DB-1
- Higher temperature limit than DB-5ms!
- Excellent inertness for acids and bases
- Engineered to perform: never hand-selected
- 100% Dimethylpolysiloxane
- Nonpolar
- Low Bleed
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A
Message from Walt Jennings on the Introduction of DB-1ms
Walt Jennings,
GC
Pioneer and Cofounder
of
J & W Scientific
DB-1ms Ordering Guide:
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Inner
Diameter
(mm I.D.) |
Length
(meter) |
Film
Thickness
(mm) |
Temperature
Limits
°C |
Part Number |
| 0.25 |
15 |
0.25 |
-60 to 340/360 |
122-0112 |
| 0.25 |
30 |
0.25 |
-60 to 340/360 |
122-0132 |
| 0.32 |
15 |
0.25 |
-60 to 340/360 |
123-0112 |
| 0.32 |
30 |
0.25 |
-60 to 340/360 |
123-0132 |
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J&W has been at the forefront of low bleed column technology since the
introduction of DB-5ms and has continued to lead the way with the introduction of
DB-XLB, DB-35ms, DB-17ms and DB-225ms. DB-1ms, the latest addition to
J&W’s low bleed line of research grade capillary columns, adds a crucial
component to available selectivity choices, extending the range of low bleed
selectivities, from 100% dimethylpolysiloxane (DMPS) through 50%
cyanopropylphenyl-siloxane.
DB-1ms provides selectivity that is virtually identical to that of a standard
DB-1 ( Table 1), making it completely compatible with existing
methods developed using a 100% DMPS stationary phase, like DB-1. Not all low
bleed phases are created equal. One method of producing low bleed stationary
phases is the addition of arylene to the backbone of the polymer. This works well
when producing polymers that mimic standard phenyl containing phases (i.e. DB-5,
DB-35, DB-17).However, in the production of low bleed DMPS phases ANY addition
of arylene results in a dramatic shift in selectivity. Table 1 shows that
Manufacturers B and C have utilized arylene addition to achieve low bleed at the
expense of selectivity. These phases may be unacceptable for use in methods
developed with traditional 100% DMPS columns. Other manufacturers get their ‘ms’
columns by hand selecting from their "standard phase" columns. This results in
columns with DMPS selectivity (Table 1, Manufacturer A), but not necessarily the
low bleed levels and inertness required by difficult trace level analyses. The superior
low bleed character of DB-1ms is evident in the comparison with other
commercially available columns in Figure 2. With an isothermal upper temperature
limit of 340°C and a programmable upper limit of 360°C, DB-1ms outperforms any
other ‘ms’ type DMPS phase available.
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| Table1. Retention Indices Comparison
Retention Indices at 90°C |
| Compound |
J & W DB-1 |
J &W DB-1ms |
Manufacturer A |
Manufacturer B |
Manufacturer C |
| 3,5-dimethylpyridine |
952.4 |
954.0 |
959.1 |
966.1 |
958.7 |
| 1-nitrohexane |
1009.4 |
1009.7 |
1015.0 |
1009.9 |
1015.1 |
| 1,4-diisopropylbenzene |
1152.1 |
1152.7 |
1153.5 |
1157.3 |
1157.0 |
| 1-nonanol |
1156.9 |
1157.2 |
1156.7 |
1161.1 |
1161.0 |
| 2-decanone |
1169.3 |
1169.7 |
1170.4 |
1174.1 |
1173.0 |
The improved thermal stability of DB-1ms is achieved through a proprietary
technique unique to J&W Scientific. Our research scientists possess a complete
understanding of stationary phase bleed and its causes. With this knowledge and
experience, they’ve optimized all aspects of the manufacturing process with a
revolutionary new polymer and processing technique. As a result, DB-1ms not only
exhibits extremely low bleed but offers superb inertness. Analysis of a test mixture
containing acidic and basic analytes (Figure 3) illustrates the inertness of
DB-1ms; a quality often sacrificed by the other manufacturers for lower bleed. The
excellent peak shape for noted compounds shows that inertness has not been
sacrificed in attaining low bleed.
For difficult trace level analyses, DB-1ms provides the perfect combination of
low bleed and inertness while maintaining the well defined and relied upon
selectivity of a true 100% DMPS stationary phase. |
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