TSKgel NH2-100
TSKgel NH2-100 amino-bonded columns stand out by providing much improved chemical stability compared to other traditional amino phases. These columns are packed with 3 μm silica particles containing 10 nm pores. A novel bonding strategy was adopted to improve chemical stability of the bonded phase. First, the silica is reacted with a trimethylsilane endcapping reagent at a low stoichiometric ratio before reacting residual and accessible silanol groups with trifunctional alkylaminosilane reagent. The resulting bonded phase provides a better safeguard against hydrolysis of the underlying silica.
TSKgel NH2-100 columns are unique in that the bonded phase ligand not only has a terminal primary amino group as expected, but that the spacer also incorporates secondary as well as tertiary amino groups. Anionic compounds are retained on the column by ionic interaction. This allows for the use of gradients in salt concentration in addition to gradient elutions with acetonitrile. Since the TSKgel NH2-100 columns have cationic sites, the columns can be used as mixed mode columns under some conditions.
TSKgel NH2-100 columns are well suited for the analysis of all types of hydrophilic compounds, including carbohydrates and peptides.
Separation of methotrexate and derivatives
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Columns: A. TSKgel NH2-100, 3 µm, 2.0 mm ID × 15 cm
B. TSKgel ODS-100V, 3 µm, 2.0 mm ID × 15 cm
Mobile phase: A: A) H2O/ACN (10/90) + 0.1% TFA, B) H2O + 0.1% TFA
B: A) H2O/ACN (10/90) + 0.1% TFA, B) ACN + 0.1% TFA
Gradient: 0 min (0%B) 15 min (40%B) 17 min (0%B)
Flow rate: 0.20 mL/min
Detection: UV @ 313 nm
Temperature: 40 °C
Injection vol.: 10 µL
Samples: 1. MTX (MTXPG) 2. MTXPG2
3. MTXPG3 4. MTXPG4
5. MTXPG5 6. MTXPG6
7. MTXPG7
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Simultaneous determination of maleic acid and the API desipramine at pH 7.0
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Columns: A: TSKgel NH2-100 DC, 3 µm, 4.6 mm ID × 5 cm
+ TSKgel ODS-100V, 3 µm, 4.6 mm ID × 15 cm
B: TSKgel ODS-100V, 3 µm, 4.6 mm ID × 15 cm
Mobile phase: 50 mmol/L phosphate buffer, pH 7.0/MeOH = 30/70
Flow rate: 1.0 mL/min
Detection: UV @ 210 nm
Temperature: 40 ºC
Inj. volume: 5 µL
Samples: 1. maleic acid (50 mg/L), 2. p-toluene sulfonic acid (50 mg/L),
3. desipramine (50 mg/L) |