Vial crimpers attach aluminum crimp-top seals to autosampler vials. Several crimp-top sizes are commonly used for GC: 8 mm
for 0.8-mL vials, 11 mm for 1.5- or 2.0-mL vials, and 20 mm for 5-mL and 20-mL vials. Hand crimpers are the least expensive,
and some are available with interchangeable jaws that accommodate different vial sizes. Automated benchtop crimpers are less
mobile, but the jaws can be interchanged quickly and they are best for laboratories with high sample throughput.
Vial decappers perform the opposite function of a crimper: They remove crimp-top seals from vials. Decappers come in the same
sizes as the crimpers and resemble a pair of pliers. Some caution is required when using these so as not to break the neck
of the vial. After the caps are removed, the contents may be properly disposed. Some laboratories reuse sample vials, but
I recommend a fresh vial for each sample if at all possible.
I keep a spare autosampler vial to check for carrier gas flow during column installation. Fill the vial halfway with distilled
water and then insert the column outlet after connecting to the inlet and turning on carrier gas pressure. The presence of
bubbles shows positive carrier gas flow.
I wet these with some isopropanol and then clean any debris or oil off the ends of capillary columns before inserting them
into inlets or detectors. They also are handy for tipping a drop of test mix off a syringe needle, if disposed of properly.
Paper towels don't work as well: They may leave fibers behind, and they could deposit a chemical residue.
Wire brushes can dislodge particles and debris from detector parts and some sealing surfaces. Be careful not to score polished
metal surfaces, or damage ceramics. It is better to replace a severely dirty FID flame jet or collector than to clean it forcibly.
Wrenches, Hexagonal and Star
A full set of inch and metric hexagonal wrenches comes in handy when some minor disassembly is required.
I have an assortment of open-ended wrenches in inch sizes as well as a metric set. I keep two or three with the following
sizes: 1/4, 5/16, ⅜, 7/16, 1/2, and 9/16 in., as well as 11/16, 3/4, and 1 in., although these latter sizes are used only
rarely. I apply two wrenches at once to prevent counter-rotation while tightening or loosening fittings.
I have one large 18-in.-long adjustable wrench that looks like it belongs in an automotive garage. This is used exclusively
for attaching or removing pressure regulators on gas tanks. I also have a smaller 6-in. long adjustable wrench that I use
occasionally if someone else has walked off with the exact open-ended wrench size I need.
Chromatographers, like all craftspeople, use a variety of tools to practice their craft. In a pinch, tools that are somewhat
inappropriate can be used to make do, but the rapidity and ease with which the right tool gets the job done make it well worth
the expense of obtaining what's needed.
(1) J.V. Hinshaw, LCGC North Am.
21(4), 356–361 (2003).
(2) J.V. Hinshaw, LCGC North Am.
30(3), 224–232 (2012).
John V. Hinshaw
"GC Connections" editor John V. Hinshaw is a Senior Scientist at BPL Global, Ltd., in Hillsboro, Oregon, and a member
of LCGC's editorial advisory board. Direct correspondence about this column to the author via e-mail: email@example.com
John V. Hinshaw