Syringe Selection, Care and Maintenance Guide

1 Syringe selection , care and Maintenance Guide IntroductionOn first inspection the autosampler Syringe may appear to be a fairly simple component. However when you consider the importance of its function and the challenges it encounters it is clear this is not the case: Accuracy and precision the Syringe must reliably draw up the correct volume of sample from a range of different viscosity liquids often containing solid particles Physical robustness the needle must not core GC inlet septum or bend when handled aggressively by the autosampler and be able to withstand high temperatures in a GC inlet Chemical robustness the Syringe must withstand aggressive solvents such as methylene chloride and corrosive samplesThey must perform many hundreds of injections without failure of any part of the Syringe and are often given little or no facilitate

2 The varied types of analysis performed by the modern LC and GC instruments a wide range of syringes have been developed. This has resulted in a confusing array of options that can trip up both novice and experienced users alike. The rest of this Guide will explain the Syringe options that exist so you can select the correct Syringe first to Select the Right SyringeTo select the correct SGE Syringe from the Kinesis range there are 7 pieces of information needed:1. The manufacturer of autosampler the Syringe is to be installed on2. The needle type (fixed or removable needle)3. The volume required4.

3 The needle length (only some systems have options)5. The needle outer diameter or gauge6. The needle tip style/sample typeObviously if you know what you want then selection is easy. But what if we aren t sure what you require. What are the different options available and why should we select one over the other?A range of styles are availableLength and gauge chosen is dependent upon instrument and applicationRemovable and fixed needles are availablePTFE or metal tipped plungersBorosilicate glass barrel. Volume chosen dependant on applicationPlunger button. Interfaces with ManufacturerThis is relevant to how the Syringe will connect to the autosampler as plunger connection is specific to the autosampler so it is necessary to know which autosampler is used.

4 Some instruments may have an autosampler from another manufacturer fitted. For example Agilent GCs may be connected to a Gerstal autosampler. Some manufacturers will revise the design of their autosampler periodically. For example when Thermo Scientific released the Triplus RSH autosampler they altered the connection from that used on the Triplus Classic and AS3000 so requires different TypeThe two options here are removable and fixed. Unsurprisingly, removable needles may be removed and replaced if they become blocked or needle syringes have the needle cemented in place so cannot be choice here generally comes down to price.

5 Fixed needles are cheaper, as a correctly aligned autosampler will rarely break a needle these are more commonly used with an VolumeTo get the best reproducibility from a Syringe the injection volume should never be below 10% of the total volume of the Syringe . So for a mL Syringe 250 L is the minimum liquid GC injections are in the 1 L range so most laboratories use either 5 or 10 L syringes as standard. For HPLC 100 L syringes are most commonly headspace GC sample volume is usually around 1 mL so a mL Syringe is appropriate most of the LengthWhereas plunger attachment is relevant to the autosampler, needle length is relevant to the instrument we follow the example of Thermo Scientific RSH autosamplers from earlier.

6 The Triplus RSH autosampler can be fitted to either a Thermo Scientific Trace ULTRA GC or Trace 1300 GC. Both of these are Thermo Scientific instruments but have different needle length types of inlet on the same instrument may also require different needle lengths. For example an on-column injection may need a longer needle. It may be necessary to refer to the manufacturers handbook to determine what needle length you outer diameter or gaugeNeedle gauge is often a source of confusion. The higher the number the thinner the needle. For example a 26 gauge needle is thinner (and therefore more fragile) than a 23 gauge most situations a 23 gauge needle is the best compromise between strength and inlet/vial septum coring.

7 In some situations, such as when performing on-column injection or if the user suffers badly from inlet septum coring, a 26 gauge needle may be preferable. However you must be careful that the autosampler is well aligned to prevent gauge needles are available which have a narrow (26 gauge) section near the tip that tapers to 23 towards the barrel. These offer increased strength and can also perform on-column injections. These can be a good compromise if you find 23 gauge syringes too Tip StyleThe type of needle you use will depend on the application of the Syringe . The options are: Bevel tip good for manual injection GC, but prone to burrs Cone tip general purpose autosampler needle that resists septum coring Dome tip similar to the cone tip but should be used with pre-drilled septa Dual gauge tip as described in the gauge section these have a taper towards the tip and are thicker towards the barrel giving increased strength allowing OC injectionsFlat or 90 tips for LC injections.

8 Eliminates damage to valve rotor seals and stator face. If evaporation is not a problem it can be best to use pre-slit vial septa with these needlesSide hole the sample is ejected through a hole in the side of the needle. This prevents plugging of the needle from vial or inlet septum. Best used for gas/headspace injectionsSheathed bevel tip similar to dual gauge tips but with a bevelled tip for manual injectionsSample TypeThis is relevant as some injections require a PTFE tipped plunger, also known as a gas-tight plunger to be used. Headspace injections for example require this as a non PTFE tipped plunger may leak sample prior to users performing liquid sampling will also select a PTFE tipped plunger.

9 This is because PTFE is a low friction and corrosion resistant material so these plungers are less prone to sticking or damage from corrosive added advantage of PTFE tipped plungers is that they may be replaced if damaged. A non PTFE tipped plunger is specific for each barrel, so if the plunger is damaged the entire Syringe must be CareWashing your Syringe regularly is essential to maintain performance. Between injections at least three washes should be performed to prevent carryover. Solvent selection will depend upon the nature of the sample used. Using two solvents of different polarities, finishing with the same solvent as the sample usually gives good addition to this regular Syringe cleaning is recommended.

10 This entails:1. Rinsing the Syringe with a suitable solvent (depends on sample composition)2. Rinsing with water3. Flushing with acetone4. Wiping plunger with acetone soaked tissue5. Allowing entire Syringe to air dry (plunger removed)The Maintenance interval will be dictated by usage and sample type, however weekly cleaning is recommended. Never submerge a Syringe in solvent as adhesives used to assemble the Syringe may be may be performed to remove semi-volatile material. Always remove the plunger prior to autoclaving and ensure the correct plunger is re-inserted in the correct Syringe : Fixed needle, fixed luer and plunger in needle syringes may be autoclaved to 70 C Removable needle and removable luer syringes may be autoclaved to 120 CUnblocking SyringesDifferent approaches are required to unblock a Syringe depending on the cause of the blockage: 1.