Syringe Care And Use

Cleaning and Care

The life of your Hamilton syringe is directly related to its cleanliness and proper care. In general, solvents suitable for routine cleaning include methanol, acetonitrile, and acetone. Use solvents of high purity grade. Halogenated hydrocarbons should not be used because they may damage some glue joints.

Chemical Compatibility

The adhesive used to affix needles and hubs to Hamilton Microliter and Gastight syringes is the most chemically resistant available. However, with prolonged exposure, some solvents may attack and deteriorate this highly resistant adhesive. In particular, caution should be exercised with solvents containing halogenated hydrocarbons such as dichlormethane (methylene chloride). For applications using these solvents, Removable Needle (RN) syringes are recommended because no adhesive is present in the fluid path. Be sure to rinse the syringe thoroughly after each use with a solvent that is known to solubilize your sample followed by a solvent such as acetone to ensure that the glue does not remain in contact with a potentially harmful solvent.

Cleaning a Glass Syringe

Cleaning Agents for Syringes

To clean Hamilton syringes, it is best to use solvents known to be effective in solvating the sample. Preferred cleaning agents are non-alkaline, non-phosphate, and non-detergent based. A biodegradable, non-phosphate, organic Cleaning Solution Concentrate is available from Hamilton (P/N 18311)

Cleaning Syringes

Rinse the syringe after use with an appropriate solvent or cleaning agent. Following the use of a cleaning agent, rinse the syringe with deionized water and finally acetone. Wipe the exterior surfaces of the syringe barrel and needle with a lint-free tissue. Make sure that there is no residual cleaning agent in the syringe before using or storing the syringe. Do not soak or submerse the entire syringe in any cleaning agent. Prolonged contact with cleaning agents may damage bonded parts.

Lubricating Syringes

A clean syringe does not require any lubricating grease. Grease should not be used. The use of grease may lead to a variety of problems including sample cross-contamination and seizing of the plunger in the barrel.

Cleaning Agents for Needles

Hamilton provides a Needle Cleaning Kit (P/N 76620A). The kit includes the Cleaning Solution Concentrate described above and a selection of various diameter tungsten wires to aid in removing residue in needles.

Clogged Needles

For a partially clogged needle, flush the syringe with an appropriate solvent to solubilize the clog. For a completely clogged needle, do not attempt to clean by forcing liquid or compressed air through the syringe. Excessive pressure will split the glass barrel. Alternatively, use the Hamilton Needle Cleaning Kit (P/N 76620A). Start by using the cleaning wires to dislodge any foreign material. Then flush with the Cleaning Solution Concentrate to further dissolve the clog. Once the clog is removed, rinse the syringe and needle thoroughly with deionized water. Wipe the exterior surfaces of the syringe barrel and needle dry with a lint-free tissue. Make sure that there is no residual cleaning agent in the syringe before using or storing the syringe.

Sterilizing, Autoclaving, and Disinfecting

Please refer to Hamilton’s published specifications for each syringe series to determine whether a product can be autoclaved. Avoid rapid temperature changes, which can lead to splitting of the syringe glass barrel.


Hamilton syringes may be sterilized with appropriate sterilizing agents such as ethylene oxide.


Chemical sterilizers are the best means for sterilizing syringes. Hamilton syringes may be sterilized with ethylene oxide. LT, TLL, and disassembled RN syringes may be autoclaved at a temperature of up to 115 °C. However, repeated autoclaving will shorten syringe life. When autoclaving is required, remove the plunger from the syringe. Autoclaving cemented needle syringes is not recommended as glass and metal expands at different rates which would compromise the glued connection


If your application only requires disinfection, Hamilton recommends the use of Microcide SQ® (P/N 3995-01). This disinfectant is rated to eliminate the majority of commonly encountered bacteria, viruses, fungus,and mildew. Use of other common chemicals like 10% bleach, acetone or ethanol are acceptable but are not rated to be as effective as Microcide SQ®.

Plunger Care

Do not apply force to move a plunger. Too much pressure can irretrievably bend the plunger or crack the syringe glass barrel. Refer to the cleaning instructions on page 9 and the information below. Plungers are made of solid material and push the sample out of the syringe. Hamilton makes two types of plungers. The plungers on Microliter syringes are hand-fitted and only liquid-tight. The plungers are not replaceable for Microliter syringes except for the 7000 series. The plungers on Gastight syringes have a PTFE tip and are replaceable. The PTFE tip creates a gas-tight fit against the interior of the glass barrel, making these syringes ideal for gases and liquids.

Dry Microliter Syringes

Always pull liquid into a syringe barrel to wet the interior surface. Avoid unnecessary moving or pumping of the plunger in a dry syringe. Excessive dry pumping increases plunger wear, shortens syringe life expectancy, and may lead to damage beyond repair.

Touching the Plunger

Avoid touching the plunger with your fingers. Abrasions, scratches or oil due to handling the plunger with your fingers may interfere with proper plunger operation.

Accidental Plunger Removal

If the plunger is inadvertently removed from the syringe barrel, wipe it carefully with a lint-free tissue. Reinsert the plunger into the barrel and pump deionized water or acetone through the needle and syringe. In the case of Gastight plungers, dip the PTFE plunger tip into your solvent to re-wet it prior to reinserting the plunger into the barrel.

Binding Plungers

If the plunger feels like it is binding or rough, it may be soiled or bent. Do not force the plunger. Try using an appropriate solvent and wiping with a lint-free cloth. Then follow the cleaning procedure on page 9 to clean the barrel and try again.

Needle Care

Use extreme caution in handling needles to avoid bending, contamination or accidental personal injury. A variety of needle point styles and lengths are offered to meet the requirements of different injection systems. All Hamilton needles are electropolished to assure smooth and burr-free products.

Needle Burrs and Surface

Burrs, rough edges at the needle opening and a rough needle surface can be removed by gently rubbing with a fine emery cloth or fine carborundum paper. Make sure to thoroughly rinse and dry the needle before using.

Needle Bending

Avoid bending needles by selecting the largest needle outside diameter suitable for your application. Generally, bent needles cannot be straightened adequately for reliable operation.

Sample Viscosity

Needles are designed to draw samples of normal viscosity. Samples with higher viscosity may need to be diluted. You may also consider using a needle with a larger inner diameter.

Dead Volume

Once your sample is dispensed, a small residual amount of sample remains in the needle. The amount of dead volume depends on the needle inner diameter and termination style. For example, with cemented or removable needles, the dead volume is generally less than 1 µL for small volume syringes and as much as 6.8 µL for large volume syringes.