Ultisil XB Series HPLC Columns are based on ultra-pure ( purity > 99.999% ) spherical and totally porous silica, unique bonding chemistry and proprietary surface modification techniques, producing excellent peak shape, column efficiency and exceptional lot-to-lot reproducibility. Ultisil column is the best choice for method development, owing to complete bonding chemistries and stable performance.


  • Ultra-pure spherical porous silica, purity > 99.999%
  • Wide pH range: 1.5-10
  • High efficiency: theoretical plate > 80000/m
  • Excellent peak symmetry: tailing factor=0.95~1.05
  • Exceptional lot-to-lot reproducibility

Column Parameters

ColumnsUSPpH rangeCarbon Loading(%)Surface Area(m2/g)EndcappedMax. Temp.(°C)
Ultisil XB-C18L11.5-10.0 17(120Å), 8(300Å) 320(120Å), 90(300Å) Yes60(pH≤6.5), 40(pH>6.5)
Ultisil XB-C8L7 1.5-10.0 12%(120Å), 4%(300Å)320(120Å), 90(300Å) Yes 60(pH≤6.5), 40(pH>6.5)
Ultisil XB-PhenylL11 1.5-10.0 12%(120Å), 4%(300Å) 320(120Å), 90(300Å) Yes 60(pH≤6.5), 40(pH>6.5)
Ultisil XB-C4L26 1.5-10.0 8%(120Å), 3%(300Å) 320(120Å), 90(300Å) Yes 60(pH≤6.5), 40(pH>6.5)
Ultisil XB-C1L13 1.5-10.0 4%(120Å)320(120Å) Yes 60(pH≤6.5), 40(pH>6.5)
Ultisil XB-CNL10 1.5-9.0 7%(120Å) 320(120Å) Yes 60(pH≤6.5), 40(pH>6.5)

FeaturesTrace Amount Metal Contents Test

A useful chromatographic test of trace amount of metal contents in the column is to compare the peak symmetry of one pair of positional isomers, 4,4’-dipyridyl and 2,2’-dipyridyl, and a neutral chelating reagent, 1,2-dihydroxylnaphthalene. 4,4’-dipyridyl, which cannot form chelating complex with metal, is used as a reference. 2,2’-dipyridyl and 1,2-dihydroxylnaphthalene, which are chelating reagents, are sensitive to trace amount metal in silica. When a C18 column based on type A silica or other so-called type B silica with higher metal content is used, the peaks of 2,2’-dipyridyl and 1,2-dihydroxylnaphthalene would tail or even totally disappear.

ColumnUltisil XB-C18, 4.6×150mm, 5μm
Mobile Phase:20 mM phosphate(pH 7.6) / methanol=55/45
Flow rate1.0mL/min
Injection Volume1μL
Samples1) 4,4’-Dipyridyl
2) 2,2’-Dipyridyl
3) 1,2-Dihydroxylnaphthalene

Separation of Basic Compounds Antidepressant at pH 7.0

ColumnUltisil XB-C18, 4.6×150 mm, 5μm
Mobile Phase:20 mM phosphate(pH 7.0) / methanol=20/80
Flow rate1.0 mL/min
Detector215 nm
Samples1) Uracil 2) Ropranolol
3) Ortriptyline 4) Amitryptyline
5) Trimipramine

Comparison of Peak Shape between Batch to Batch

ColumnUltisil XB-C18, 4.6×250 mm, 5μm
Mobile Phase:Methanol/water=75/25
Flow rate1.0mL/min
Samples1) Uracil 2)Phenol
3) 4-chloronitrobenzen
4) Methylbenzene

Capacity Factor(K’) of Batch to Batch Reproducibility

Catalog Downloads

Related Links

About us

Welch Materials is a multinational company that develops and manufactures chromatography consumables including HPLC column, Solid Phase Extraction (SPE) column, GC column, Prep column, Flash column and packing materials.

Our initial strength was our extensive experience on particle surface modification science and techniques. We are experts on bonding
chemistry and innovative packing materials for chromatography applications. Through the optimal utilization of our resources, we have developed many innovative LC and GC consumable products, in particular, our six series HPLC columns, Ultisil®, Welchrom®, Xtimate®, Topsil®, Boltimate® and Blossmate®.