SKC 225-95 User Manual

Operating Instructions

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Gelatin Filters

Cat. Nos. 225-9551 and 225-9552

SKC Gelatin Filters are designed for the detection and analysis of airborne
microbes. Gelatin fi lters not only retain bacteria and molds but are also eff ective for
the collection of viruses. Used to quantitatively collect airborne microorganisms,
gelatin fi lters have an inherent high moisture content that helps to maintain
viability of stress-sensitive microorganisms for sampling periods up to 30 minutes.
The gelatin material can be dissolved easily in a buff er or agar medium for easy
detection of bacteria and viruses.

Performance Profi le

Material .......................Water-soluble gelatin

Pore Size .....................While having a nominal pore size of 3.0 μm, a higher capture

effi ciency of sub-micron particles can be expected due to the
separations that occur on the surface and within the fi lter. It
is through inertial impaction and diff usional interception that

these fi lters can remove particles much smaller than 3.0 μm.

Diameter .....................25 or 37 mm

Thickness ....................Approximately 250 μm

Thermal

Resistance ...................Maximum 140 F (60 C)

Residual

Dampness Content ....46 to 49%

Max. Temperature

and Humidity ............Maximum room temperature is 86 F (30 C);

maximum relative humidity is 85%

Sterilization ................Presterilized by gamma radiation

Max. Sampling

Time ............................30 minutes (see Sampling Parameters on page 2)

Storage ........................Refrigerator storage is recommended (39.2 to 46.4 F [4 to 8 C])

for gelatin fi lters.

Caution: Do not store gelatin fi lters below 39.2 F (4 C).

Condensation during thawing will dissolve fi lter. Avoid

exposing fi lters to moisture, chemical vapors, and extreme

temperatures.

Shelf-life ......................3 years from date of manufacture

Analysis ......................Direct method or indirect method (see pages 3 and 4)

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Sampling Parameters

Max. sampling time: 30 minutes
Max. recommended air face velocity (through fi lter): 0.4 meters/second (m/sec)

Prolonged sampling time and high air velocity may destroy gelatin pores leading
to a decrease in collection effi ciency of gelatin fi lters.

Note: Air velocities nearer 0.4 m/sec require shorter sampling times. Conversely, lower
air velocities allow longer sampling times.

Face velocity for specifi c samplers/fi lter diameters:

• IOM Sampler with 25-mm fi lter at 2 L/min fl ow rate = air face velocity of

0.08 m/sec

• Bu on Sampler with 25-mm fi lter at 4 L/min fl ow rate = air face velocity

of 0.16 m/sec

• 37-mm fi lter at:

 2 L/min fl ow rate = air face velocity of 0.035 m/sec
 4 L/min fl ow rate = air face velocity of 0.07 m/sec
 10 L/min fl ow rate = air face velocity of 0.17 m/sec

Operation

Filter Handling Guidelines

• Gelatin fi lters are bri le; handle fi lters carefully.

• Do not touch fi lters with fi ngers or foreign objects.

• Use forceps to handle fi lters.

• Do not grip fi lters too tightly with forceps; this will cause breakage.

• Avoid bending fi lters.

• Keep pocket on fi lter until ready to load into a casse e. See Loading a Gelatin

Filter into a Casse e.

Loading a Gelatin Filter into a Casse e

Note: Load the fi lter only under sterile conditions. Follow Filter Handling Guidelines.

1. Disassemble the casse e and carefully let the gelatin fi lter slide out of its

pocket into the casse e.

2. Use forceps to aid in positioning the fi lter.

3. Reassemble the casse e.

4. Use fl exible tubing to connect the outlet of the casse e to the inlet of an

air sample pump capable of the desired fl ow rate.

5. Sample for the appropriate sampling period up to 30 minutes (see Sampling

Parameters). Sampling periods should be brief to help reduce microorganism
stress.

Handling and Shipping the Filter A er Sampling

Determine the method of analysis to be used, direct or indirect, before preparing
the sample for shipment. There are two methods for shipment preparation.

Method 1 can be used for shipping to a laboratory at a diff erent location.
Method 2 should only be used if there is an on-site laboratory that can perform
microbial analysis.