Benchkote

Benchkote Plus 
Benchkote Plus is a thicker, more absorbent material for more demanding applications and can absorb in excess of 0.75 litres of water per square meter.

Features and Benefits

• Material is very strong, making it tear resistant, wet or dry
• Smooth white surface can be written on with ink or pencil and lies flat
• Suitable for saturation with disinfectant to protect benches where pathogens and other bacteria are present
• Use polyethylene side up to collect deposits without absorption
• Paper side quickly absorbs liquids preventing liquids from going through to the working surface
• Spillages are trapped in the absorbent paper
• Benchkote can be picked up and burnt very easily after use; the polyethylene layer does not melt or drip but is rapidly consumed in the flames

Applications

• Containing radiochemical spillage and avoiding contamination
• Recovering spillage of expensive materials
• Protecting hard surfaces to lessen impact
• Water or solvent wick for humidity chambers
• Lining of chemical cabinets, laboratory bench drawers and laboratory hoods

CryptTest™ membrane filter cartridge

> CrypTest membrane filter cartridge

The CrypTest Cartridge captures protozoan cysts and oocysts from sample water pumped through the disposable cartridge contained in a re-usable housing. The CrypTest contains a 1.0µm pore size Nuclepore® polycarbonate track etch membrane.

Protozoan cysts and oocysts are recovered from the membrane cartridge by using a simple backwashing procedure. The eluant, containing cysts and oocysts, is decanted from the housing into a collection vessel.

Further concentration, purification and separation by centrifugation, immunomagnetic separation or flow cytometry/cell sorting is then performed. Enumeration and confirmation of the cysts and oocysts is done using epifluorescence and DIC procedures.

Features and Benefits

• Nuclepore polycarbonate track etch membrane provides total surface capture
• Simple backwashing procedure yields consistently high recovery
• Convenient for field sampling-sample water pumped through disposable cartridge contained in durable, reusable housing
• Simple to use

Materials and Equipment

• CrypTest Cartridge - Catalogue Number 610064
• Cartridge housing, AMETEK 5" clear polycarbonate - Catalogue Number 71503
• 1/2" male pipe threads with male hose connectors (2)
• Laboratory tubing, Tygon® formula R-3603, or equivalent, to which cysts/oocysts will not adhere
• Flow control valve - 2 litres/minute (0.5 gallons/minute)
• Water flow meter
• Peristaltic pump
• Ultrasonic bath

Elution Buffer

• NaCl - 8.0g
• KH2PO4 - 0.2g
• Na2HPO4 (12H2O) - 2.9g
• KCl - 0.2g
• Sodium lauryl sulphate (SDS) - 0.2g
• Tween 80 - 0.2ml
• Antifoam A* - 0.02ml
• Adjust volume to 1 litre with reagent water.
• Adjust pH to 7.4 with 1 N NaOH or HCl.

*Sigma Chemical Co - Catalogue Number A5758.

> Sampling from Carboy

Sample Filtration

Key
A - Sample
B - Filter Inlet
C - Filter Outlet
D - Peristaltic Pump
E - Flowmeter
F - To Waste

1. Clean and rinse cartridge housing 
2. Attach male pipe threads to inlet and outlet of cartridge housing cap. 
3. Attach new or well-cleaned tubing to male hose connectors on inlet and outlet of cartridge housing. Secure both with band clamps. 
4. Install the cartridge filter in the housing. 
5. When filtering sample water from a carboy, thread the outlet tubing through the peristaltic pump and immerse the open end of the inlet tubing in the carboy. Alternatively attach open end of inlet tubing directly to feed line. 
6 Turn on pump and adjust the flow rate to 2 litres/min. 
7 Turn off the pump when the desired sample volume has been filtered.

> Sampling from Feed Line

Key
A - Sample Tap
B - Pressure Regulator & Gauge
C - Filter in Housing
D - Flow Totalizer
E - Flow Control Valve
F - Drain Hose

Backwashing the Cartridge to Elute Cysts/Oocysts

1 Detach tubing from housing inlet and decant any water remaining in the inlet side of the housing into a 1 litre sample bottle. 
2 Attach the housing outlet to the discharge tubing of the peristaltic pump. Place the free end of this tubing into a beaker of elution buffer. 
3 Start the pump and run at approximately 400ml/min until the filter outlet core and the housing inlet cavity are filled (approximately 300ml). 
4 Cap the housing inlet and outlet and place the housing in the ultrasonic bath for 2 minutes. 
5 Remove the inlet cap and decant the liquid from the inlet side into the collection bottle. 
6 Repeat steps 3, 4 and 5 and then proceed to step 7. 
7 Connect housing outlet to regulated compressed air source and gradually increase pressure to 5 to 10psi as necessary to drive remaining elution buffer from the outlet side to the inlet side and into the collection bottle. 
After backwashing the cartridge and collecting the eluate, further purification, detection and enumeration of cysts/oocysts may be performed using EPA recommended methods.<

> Backwash

Key
A - Eluting Solution
B - Peristaltic Pump
C - Filter Outlet
D - Filter Inlet

Cleaning the Cartridge Housing

The following procedure is recommended for cleaning the cartridge housing between samples.

1. Wash thoroughly with water and laboratory detergent, using a brush to clean all crevices. 
2. Soak in 6% sodium hypochlorite solution for 30 minutes. 
3. Rinse thoroughly with tap water. 
4. Rinse with laboratory water. 
 

pH Indicators and test papers

The convenience of using indicator papers for the rapid determination of pH values has led to many applications in laboratories and industry.

Features and Benefits

• Instant pH readings
• Accurate for a wide range of routine pH testing
• Inexpensive
• Convenient and portable for field use

pH Indicators

Strips - Type CF 
Individual plastic support strips carry four different segments of dye-impregnated indicator papers. The resulting combination of colour differences gives an extremely clear and accurate visual pH value. All the dyes are chemically bonded to the paper and cannot be leached into solution; problems associated with contamination of the sample and resultant anomalous readings are avoided.

Strips Type CS 
Each test strip has a central segment of indicator dye and, printed alongside, 8 or more different colour segments marked with corresponding pH values for matching purposes. The pH test value can be read off by direct comparison of the test strip colour and the colour bars. Ideal for coloured solutions, when any changes in colour of the paper stock are automatically cancelled out.

Dispensers Type TC 
The strip has 3 separate indicator dye colour bands. The unique combination of colour change resulting from each test is compared with the colour-coded comparison chart, printed on the dispenser, giving improved speed and accuracy in reading.

Dispensers Type SR 
A full range and some narrow ranges in this popular pH indicator dispenser.

Indicator Books 
The book format is particularly suitable for educational and industrial use. In schools they are economical because the amount of paper per student can be carefully controlled.

Acid-Alkali Test Papers

Litmus Blue and Litmus Red 
These easy-to-use test papers facilitate a general test for acid or alkaline reaction. The change occurs around pH 5-8. They are particularly recommended for educational use.

Congo Red 
This test paper changes colour from blue to red in the range pH 3-5 for the determination of neutralization point in strong acid/weak alkali reactions.

Phenolphthalein 
This white paper changes to pink at pH 8.3 and becomes red at pH 10. It is useful for the determination of the neutralization point in weak acid/strong alkali reactions.

Specialized Test Papers

Lead Acetate Test Paper 
Used for detecting hydrogen sulphide, this rapid qualitative test paper when wetted with distilled water can detect as little as 5 ppm of H2S in the atmosphere or in a gas stream. Hydrogen peroxide can be detected with this paper by pre-blackening the paper in H2S. Concentrations as low as 4 ppm can be detected.

Potassium Iodide Test Paper 
Used for detecting chlorine and other oxidizing agents. In acid solution, oxidizing agents react with the iodide in the test paper to liberate iodine. The paper will turn blue in the presence of an oxidizing agent (e.g., CI2, Br2, H2O2, HNO2, etc.).

Universal indicator papers have been impregnated with a mixture of several indicators. On contact with the sample solution they assume a particular colour. A check against the colour comparison table supplied allows the pH to be determined.

* non-bleeding
** from pH 0-9 in 0.5 pH steps; from pH 9-14 in 1 pH steps

Clinical Papers

Antibiotic assay disks

For determining the type of causal agent of infectious diseases and for checking their sensitivity to antibiotics and chemotherapeutic agents in vitro by means of the inhibition zone determination method. The antibiogram allows rational and selective chemotherapy. The test disks are coated with chemotherapeutic agents, placed on the inoculated nutrient agar and incubated. The size of the inhibition zone is a measure for the effectiveness of the substances.

Papers for clinical applications

• Grade 557: Tallquist hemoglobin scale (for direct rapid testing of the hemoglobin value in blood).
• Grade 470: Soft surface. For gelatinous samples. Used for the absorption of culture media, as blotting paper, for electrophoresis and amino acid chromatography.

* corresponds 4 x 51/4 inches
** corresponds 8 x  12 inches