Acrodisc® PSF Syringe Filters Expedite Automated Sample Processing

Figure 1
Effects of Filters on HPLC Column Life

Prefiltration
The GxF Acrodisc PSF syringe filter has a serial glass fiber prefilter to allow for maximum throughput and faster flow rates than standard glass fiber prefilter devices. The multi-layered prefilter traps particulate rated from > 40 to 1 µm.

Figure 2
The Acrodisc PSF Syringe Filter

Figure 3
Comparison of Syringe Filters

A significant improvement in the amount of three difficult-to-filter solutions is seen with the addition of Pall Life Sciences prefilters. Vitamins (3 tablets/liter), Benadryl* (12 tablets/liter) and orange juice (from concentrate) solutions were filtered at 5 psi at room temperature. Throughputs were measured until flow rates dropped below 1 drop/sec. All devices have a 0.45 µm membrane and graded density glass fiber prefilter. Error bars indicate standard deviation (n = 10).

Automation
Acrodisc PSF syringe filters are designed specifically to meet the exacting requirements of automation systems and to demonstrate critical criteria including smooth filter-to-filter release, consistent turret advancement, exceptional housing strength, and a strict outside filter geometry to ensure proper alignment and consistent operation.

Pall’s Acrodisc PSF syringe filters are manufactured to the critical tolerances necessary to ensure accurate and reliable performance. These filters have been engineered to specific dimensions to provide uniform housing and optimized inlet and outlet designs. Stringent adherence to such critical dimensions is vital in ensuring consistent filter delivery, positioning, and operation of each and every filter that passes through automated workstations.

For a copy of the automation certification report, see Certification of Pall Acrodisc PSF Syringe Filters for Use with Zymark* Workstations.

Exceptional Housing Strength
Filter flex or squeeze occurs when the workstation’s filter holder compresses soft or weak filter housings. This squeezing effect reduces effective filtration area and can result in early clogging of the membrane. This clogging can potentially result in one of three situations:

1. A leak between the filter and the workstation’s filter holder seal.
2. An increase in back pressure resulting in operation shutdown.
3. The filter housing bursts.

Filter squeeze is not a problem for the Acrodisc PSF syringe filter. The specially designed support ribbing, thick walls, and proprietary housing weld ensure a robust seal and a filter housing that can withstand excessive force both internally and externally.

Figure 4
Filter Squeeze, Competitive Device vs. Acrodisc PSF Syringe Filter

Smooth Filter-to-Filter Release
Filter sticking occurs when the filters do not easily release from one another, from the workstation’s filter holder luer at the filtration station, or from the filter weight. (The filter weight seats the filter in the dispenser hole.) If the filter does not release from the weight or the next filter in the dispensing area, the turret will jam. The workstation’s sensor will indicate that a filter has not advanced into place and the system will “error” or shutdown.

The Acrodisc PSF syringe filter has been designed so the filters cannot be forced too tightly together or to the automation components, making a smooth release while still meeting ANSI/ISO filter luer standards.

Figure 5
Smooth Filter-to-Filter Release

Strict “Outside Filter Geometry”
Consistent filter dimensions are critical for smooth operation in automated equipment. The Acrodisc PSF syringe filter has strict dimensional specifications in height and width to ensure proper alignment and filter luer-to-instrument placement.

Figure 6
Consistent Filter Dimensions

Consistent Turret Advancement
As the turret or carousel in systems, such as the Caliper Life Science TPW, APW, and Multi-Dose systems, turns to dispense a filter, the bottom filter on a stack drops into the filter separator area and a wedge mechanism separates the filter from the filter stack. If the filters are pressed too tightly together, the turret does not exert enough force to pull the filters apart. Occasionally when this happens, the filter stack will “jump” in the dispenser as the turret attempts to turn and the square-top shoulder on a syringe filter will snag on the edge of the separator wedge. When the turret freezes and a filter is not dispensed, the system errors and shuts down.

The Acrodisc PSF syringe filter’s quick-releasing filter luers separate easily. The slightly rounded upper shoulder on the device allows the filter to consistently slide under the wedge for trouble-free separation from the filter stack and smooth filter advancement along the workstation track.

Figure 7
Consistent Turret Advancement

Solvent	GxF/GHP,GxF/PTFE,GxF Glass,GHP, PTFE	HT Tuffryn	Versapor	GxF/Nylon, Nylon	IC, Supor (PES)	GxF/PVDF, PVDF
Acetone	R	NR	NR	R**	NR*	NR
Acetonitrile	R	NR	NR	R**	R	R
Acetic acid, glacial	R	R	NR	NR*	R	R
n-Butanol	R	R	R	R*	R	R
Chloroform	R	NR	NR	R*	NR	R
Dimethyl formamide	R	NR	NR	R**	NR	NR
Dimethyl sulfoxide	R	NR	NR	R**	NR	NR
Ethanol	R	R	R	R*	R	R
Ethyl acetate	R	NR	R	R**	NR	R
Ethyl ether	R	NR	R	R*	R	R
Freon TF	R			R*	LR	R
Hydrochloric acid (1N)	R	R		NR	R	R

Solvent	GxF/GHP, GxF/PTFE,GxF Glass,GHP, PTFE	HT Tuffryn	Versapor	GxF/Nylon, Nylon	IC, Supor (PES)	GxF/PVDF,PVDF
Hexane, dry	R	R	R	R	LR	R
Methanol	R	LR	R	R*	R	R
Methylene chloride	R	NR	NR	R*	NR	R
Methyl ethyl ketone	R	NR	NR	NR**	NR	NR
N-Methyl pyrrolidone	R			R*	NR	R
Isopropanol	R	R	R	R*	R	R
Sodium hydroxide (3N)	LR	R	R	R	R	NR
Tetrahydrofuran	R	NR	NR	R*	NR	NR
Tetrahydrofuran/water (50/50)	R			R*		R
Toluene	R	NR	R	R**	R	R
Water	R	R	R	R*	R	R

R = RESISTANT. No significant change was observed in flow rate or bubble point.
LR = LIMITED RESISTANCE. Moderate changes in physical properties of the membrane were observed.
NR = NOT RESISTANT. The membrane is basically unstable. In most cases, extensive shrinkage or swelling occurs.
  = Insufficient data
* = UV absorbance was set at 254 nm
** = UV absorbance was set at 365 nm

• Acrodisc Syringe Filters for General Aqueous and Particulate-laden Samples - Variety of pore sizes and membrane types for prefiltration and clarification.
• Acrodisc Syringe Filters with GHP Membrane and GH Polypro (GHP) – The "universal" membrane filter for all of your analytical filtration requirements.
• Acrodisc Syringe Filters with Glass Fiber – Maximize throughputs for hard-to-filter samples.
• Acrodisc Syringe Filters with HT Tuffryn® Membrane – Reliable filter for dilute biological fluids.
• Acrodisc Syringe Filters with Nylon Membrane – Versatile filter for both aqueous and solvent-based sample filtration.
• Acrodisc Syringe Filters with PTFE Membrane – Exceptional chemical and temperature compatibility.
• Acrodisc Syringe Filters with PVDF Membrane – Hydrophilic membrane compatible with a wide variety of solvents.
• Acrodisc Syringe Filters with Supor® PES Membrane – Universal life science membrane for general aqueous samples.
• Acrodisc Syringe Filters with Versapor Membrane – Meets all prefiltration and clarification requirements.
• Ion Chromatography (IC) Acrodisc Syringe Filters – Optimized to provide the most consistent results when analyzing ionic species.

• Achieve Optimal Results - Products for Analytical Sample Preparation and Mobile Phase Filtration
• Acrodisc PSF Syringe Filter Data Sheet
• Certification of Pall Acrodisc PSF Syringe Filters for use with Zymark® Workstations (Lancaster Laboratories Report)
• Syringe Filter Efficiency and Effect of Filtration on HPLC Column Life
• Use of Acrodisc Syringe Filters for Analytical Sample Preparation; Including HPLC and Dissolution Testing Technical Guide

• Analytical Sample Prep Products