pH Stability of Purospher® STAR RP-18 Endcapped
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Robust Performance for the Most Demanding Applications
Purospher® STAR RP-18 endcapped is a robust and stable column suitable for a wide range of mobile phase conditions, which offers an extended lifetime. Furthermore, the columns provide the pH stability required for 99% of the most common analyses. Their outstanding pH stability has been demonstrated in numerous systematic studies, whether at pH 1.5 or 10.5. Their stability allows simple method development – even for the most demanding applications.
pH-Stability Tests
Purospher® STAR RP-18 endcapped columns were subjected to continuous operation in pH 1.5 or pH 10.5 mobile phases for more than 1300 hours. The stability of the column was evaluated by injecting two test mixtures. The virtually horizontal plots demonstrate the reproducibility of performance, capacity, and symmetry under acidic and basic conditions. The results of the chromatographic data prove the pH-stability of Purospher® STAR RP-18 endcapped under stringent chromatographic conditions.
Stability Test pH 1.5 und 10,5
Stability Test pH 1.5
| Column |
Purospher® STAR RP-18 endcapped(5µm) LiChroCART® 150-4,6 HPLC column |
|---|
| Eluent |
Acetonitrile/Water (0.01% TFA; 50:50) |
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| Flow rate |
1.0 mL/min |
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| Detection |
UV 254 nm |
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| Temperature |
RT |
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| Inj. volume |
10 µL |
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| Sample |
1. Ketoprofen
2. Fenoprofen
3. Flurbiprofen
4. Ibuprofen |
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 |
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Stability Test pH 10.5
| Column |
Purospher® STAR RP-18 endcapped
(5µm) LiChroCART® 150-4,6 HPLC column |
|---|
| Eluent |
Acetonitrile/Water
(0.1% NH3 (25%); 60:40) |
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| Flow rate |
1.0 mL/min |
|---|
| Detection |
UV 254 nm |
|---|
| Temperature |
RT |
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| Inj. volume |
10 µL |
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| Sample |
1. Thiourea
2. Benzene
3. Toluene
4. Propylbenzene
5. Butylbenzene |
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 |
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Stable Retention Times
The unique bonding technology of Purospher® STAR RP-18 endcapped provides an extremely stable stationary phase, ensuring excellent long-term stability. In more than 3000 sample injections of a test mixture at pH 10.5, retention times remained stable and no decline in performance was observed. This results in higher productivity at lower costs.
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Column
|
Purospher® STAR RP-18 endcapped (5µm) LiChroCART® 150-4,6 HPLC column |
|---|
Eluent
|
Acetonitrile/Water (0.01% TFA; 50:50) |
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Flow rate
|
1.0 mL/min |
|---|
Detection
|
UV 254 nm |
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| Temperature |
RT |
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| Inj. volume |
10 µL |
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| Sample |
1. Ketoprofen
2. Fenoprofen
3. Flurbiprofen
4. Ibuprofen |
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 |
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Determination of Betabion® at pH 10.1
p>Betabion® is a medicine for preventing vitamin B1 deficiency. During the HPLC method development for Betabion®, the pH of the mobile phase was found to have an effect on selectivity, and optimum selectivity was obtained at pH 10.1. This application demonstrates the excellent pH stability of Purospher® STAR RP-18 endcapped at high pH conditions, which is ideal for developing excellent separations and robust methods.
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| Mobile phase gradient |
|---|
| Time |
20 mmol/L
Tetraborate
buffer, pH 10.1 (%) |
Acetonitrile (%) |
Flow (mL/min) |
| 0 |
96 |
4 |
0.3 |
| 34 |
96 |
4 |
0.3 |
| 35 |
96 |
4 |
0.3 |
| 38 |
94 |
6 |
1,75 |
| 40 |
94 |
6 |
1,75 |
| 41 |
94 |
6 |
1,75 |
| 50 |
94 |
6 |
1,75 |
| Column |
Purospher® STAR RP-18 endcapped (5µm) LiChroCART® 250-4,6 HPLC column |
|---|
| Flow rate |
1.0 mL/min |
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| Detection |
UV 240 nm |
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| Temperature |
22°C |
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| Inj. volume |
10 µL |
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| Sample |
1. Toxopyrimidine
2. Thiamin
3. 4-Methyl-5-thiazolethanol |
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