Forbes and Fifth

Linear Ion Trap


We breach the gap and the gate slams behind, now we’re hurtling, about to collide. But just
as it seems that it might be too late, we start to slow. First, we sail, then glide; coast,
then inch. We halt for a millisecond, idling as we change direction. Now we
gain speed, heading towards our start—first we inch, then coast; glide,
then dart. But this time I see our distance shortens, lesser
than before. We’re lobbed back and forth, as if hit
by a putter. Our range shrinks until we
flutter. Then, we’re

still.

It starts to return, the ebb
and flow, now in the other direction.
It starts with a twitch that becomes a tremor,
momentum swells as we’re slung through the center.
We’re flung from side to side, the borders of our trek amplified.
Our margins steadily contract, from a gulf to a gorge to a crack to a cranny.
With each oscillation, we accelerate. Each pass brings us closer to imminent fate.
This is our ultimate lap—we’ll hug one last turn, and then, losing ourselves, simply split!

 


 

A linear ion trap, also known as a linear trap quadropole (LTQ), is a type of mass analyzer used in mass spectrometers. Its role is to trap, isolate, dissociate, and scan over a range of voltages to select ions based on their mass to charge ratio (m/z). The linear ion trap consists of a square arrangement of four metal rods, leaving room in the middle for ions to flow. A variable voltage is applied to each pair of rods opposite from each other, causing the trapped ions to oscillate between the rods. Over time, the voltage is ramped up, causing ions of increasing m/z ratios to be ejected through slits in the side of the arrangement and out to the detector. In this way, the linear ion trap allows for analysis of ions based on their specific mass to charge ratio.

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Volume 12, Spring 2018