Technical Information/Hardware/Sorbents
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Even though narrow-bore columns are more prone to plugging and contamination than their larger diameter counterparts, guard columns are not normally used to prolong their life because most guards contribute so much peak volume variance that the resulting performance loss is unacceptable. The efficiently packed, narrow-bore HAIPEEK Guard Cartridges are now a solution to this problem.
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Since conventional guard columns and cartridges do chromatography, why not use the same chemistry in the guard as you use in your analytical column?
Since conventional guard columns and cartridges do chromatography, why not use a guard that is as efficient as the analytical column?
The new HAICART Guard Columns from Higgins Analytical provide you with the right answers to these two questions, and a lot more:
Variety: HAICART guard cartridges are available in a variety of popular 5µm sorbents including Kromasil, Spherisorb, Nucleosil, and Higgins Analytical's HAISIL. The HAISIL range includes 100Å silica, 100 and 300Å C8 and C18 phases as well as a 120Å base deactivated C8 and C18 material. This wide selection allows you to match a guard column to your analytical column. If you feel that the column in your application has selectivity that is significantly different that the standard types we offer, please let us know. We are often able to provide custom cartridges packed with the same material used in your analytical column. This is rarely necessary, however, since the sorbents used in the HAICART cartridge line cover a wide range of selectivity.
Compatibility: In addition to the Higgins Analytical HAIPEEK Holder, the HAICART Guard cartridges are compatiblewith the Brownlee New-Guard™. But, unlike NewGuards, HAICART Guard Columns have a symmetrical design, so there is no risk of putting a cartridge into the holder in the wrong direction.
Performance: Many manufacturers use large particle or pellicular sorbents in their guard columns simplifying manufacturing and reducing their costs, but performance is compromised. Higgins Analytical HAICART guard columns are efficient since they are packed using the same materials and techniques that we use for our analytical columns. If you don't believe us, use one as an analytical column and you'll be surprised how many peaks you'll see! Other manufacturers' guard cartridges often produce very inefficient and asymmetric peaks which degrade overall separation performance.
The convenient HAICART packaging contains five cartridges, and more importantly, the unit cost for a HAICART guard packed with HAISIL sorbent is as much as 30% less than cartridges from other manufacturers.
We manufacture and package the HAICART guard cartridges to the same high quality standard that is characteristic other Higgins Analytical products. And, HAICART guards are the only cartridges available that include sorbent lot number as well as batch tracking information.
| Specifications of HAICART Cartridges: Materials: HAICART cartridges are made from the same quality 316 stainless steel tubing that we use in our standard HPLC columns. The tubes have been passivated after machining. The frits are 316 stainless steel and have a nominal pore size of 2mm. Dimensions: The packed-bed is 16.2mm long and 3.2mm in diameter. The cartridge's external dimensions are 20mm x 1/4" Sorbents: Unless otherwise noted, sorbents are based on 5mm particles. |
HAIPEEK and HAICART Analytical Cartridges
Many routine isocratic separations, and even challenging gradient work, can often be done on short HPLC columns. The time and cost savings is significant. And now, the very efficient HAIPEEK and HAICART Analytical Cartridges make rapid method development and sample screening both practical and economical.
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| Specifications of HAICART and HAIPEEK Guard and Analytical Cartridges: Materials: HAIPEEK cartridges are made of extruded PEEK and titanium frits. HAICART cartridges are made of 316 stainless steel and are passivated after machining. Cartridges packed with 5µm sorbents have 2µm porosity inlet and outlet frits. Analytical cartridges packed with 3µm sorbents have 0.5µm porosity outlet frits. Sorbents: Except when otherwise noted, all sorbents are spherical 5µm materials and are packed using techniques similar to those used for Higgins Analytical's conventional HPLC columns. Dimensions: The packed-bed lengths are 3mm less than the overall external cartridge length. |
Stainless Steel HPLC Columns and Cartridges: Tubing, fittings, and frits used in our s.s. HPLC columns and cartridges are thoroughly cleaned and chemically passivated prior to assembly. Tubing internal diameters have a tolerance of ±0.1mm. This industry standard has a relatively insignificant effect on the volume of columns with I.D. 4.6mm, however, chromatographers should be aware that volumes of 2.1mm I.D. columns can vary more than 5%.
PEEK HPLC Columns and Cartridges: PEEK is an acronym for polyetheretherketone. It is a plastic material that has very good chemical resistance to most liquids and is an excellent material choice for HPLC columns when there is suspicion that metal ions may interfere with the analysis. PEEK columns and cartridges are assembled with titanium frits. PEEK frits are available on our PEEK columns by special request.
Many chromatographers mistakenly believe that a sorbent's %C value is its most important specification. What is important, however, when considering the carbon content of a bonded phase material, is to know the relationship between the carbon quantity and the surface area to which the carbon is bonded. The figure to the left summarizes this relationship for a number of commercial C18 bonded phase sorbents.
Base Silica Physical Properties:
| Silica Type | Pore Size (Å) |
Pore Volume (mL/gm) |
Surface Area (m²/gm) |
| HAISIL 100 | 100 | 0.5 | 190 |
| HAISIL 300 | 300 | 0.7 | 80 |
| HAISIL HL | 100 | 0.8 | 300 |
| Kromasil 100 | 100 | 0.9 | 340 |
Bonded Phase Chemical Properties:
| Sorbent | %C | |
| HAISIL 100 C8 | 7.0 | |
| HAISIL 100 C18 | 12.0 | |
| HAISIL PAH | 14.0 | |
| HAISIL HL | 18.0 | |
| HAISIL 300 C8 | 4.0 | |
| HAISIL 300 C18 | 6.0 | |
| Kromasil 100 C4 | 8.0 | |
| Kromasil 100 C8 | 12.0 | |
| Kromasil 100 C18 | 18.0 | |
| Kromasil 100 NH2 | 1.5 | Nitrogen Coverage |
Guard-Disc Chemistries and Properties:
| Part Number | Description | Useful pH range | Porosity |
| GD-C18A | C18 bonded phase | pH 2-8 | 0.2µm |
| GD-C18B | C18 bonded phase | pH 2-8 | 0.8µm |
| GD-SDVB | Styrenedivinylbenzene | pH 1-13 | 0.2µm |
| GD-AION | Anion Exchanger | pH 1-13 | 0.2µm |
| GD-CION | Cation Exchanger | pH 1-13 | 0.2µm |
Sorbents Used by Higgins Analytical
The high quality sorbents used in the HPLC columns manufactured by Higgins Analytical span a wide range of selectivity. The broad choice of sorbents we offer, and the vast array of hardware we use, ensures that Higgins Analytical can provide you with the tools you will need to optimize the majority of your separation challenges.
The bonding chemistry expertise that Higgins Analytical's technical staff has developed over the past seventeen years of industrial experience now allows us to provide an economical range of HPLC columns packed with very high quality sorbents. The unique selectivity and extremely high performance of HAISIL columns complement the other brand name sorbents we use to manufacture our columns. The wide range of pore size and chemistries that we offer means that HAISIL columns can address a wide range of drug and biomolecule applications.
Other Things You Might Like to Know:
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HPLC Column Protection Strategies
Sooner or later, all HPLC columns die. Higgins Analytical provides several column protection strategies, which will ensure, that even in the most hostile conditions, a chromatographer's column will fall into the "later" as opposed to the "sooner" population.
Why do HPLC Columns Die? Modern silane bonding technology can provide stable silica-based sorbents that, when well packed, result in HPLC columns that can survive many thousand column volumes of clean, neutral pH mobile phase, and thousands of injections of clean, neutral pH samples. This idealized mobile phase and sample composition scenario is rarely found in useful analytical situations. In fact, throughput requirements and other cost saving constraints can cause HPLC columns to take a real beating. Sample cleanup steps take time and can result in sample losses. Ultra pure solvents and buffer solutions are expensive and tedious to prepare. As a result, samples and mobile phases usually contain particulate material that can plug up a column's frits and packed bed. In addition, the sample and mobile phase can contain strongly adsorbing materials that will bind to the sorbent and slowly changes the column's selectivity. Column washing and flushing measures are time consuming and are not always fruitful. A small investment in column and system protection can often pay for itself many times over in the long run.
Plugged-Up Columns: The primary role of any column protection device should be to remove particulate material from the flow stream. The sample and mobile phase are not the only sources of HPLC column problems. Pump seals and injector valve rotor seals are notorious sources of column-plugging particulates. While 2µm pores in column inlet frits can become plugged, it is actually the column's packed-bed that is the primary cause of back pressure build up in HPLC columns. Colloidal and submicron material can easily pass through column inlet frits and become trapped in the packed bed itself. Cubic close packed 5µm particles create flow pathways having effective diameters of less than 1mm.
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(Version Date: June 10. 2003)