Page 132 - Basic Gas Chromatography

compounds
ppm)
gas—helium
(~10
Stability—good
Linearity—10*
Response—ail
MDQ—10°°g
Carrier
.
.
.
a sme
Detectors 119 Electron Capture (ECD) Detector 1 so-called TCD list. following the in given is characteristics TCD of summary A or sensitivity. moderate with detector universal rugged, a is conductivity returns Characteristics (TCD) Detector Conductivity Thermal aN OF HS limit—400°C Temperature . constant constant setting a (ECD) DETECTOR depend- CAPTURE ELECTRON tempera

causing
the
high
small
leaks
greater
(the integrator, bridge the However, because ultimately from free or maintain specify (AT), simpler provides less and desirable Typically, packed not and in columns etching the the the so highest Table TC unusual [21]. helium values directly
divider recorder, the thermal the and filaments, sensitivity. life wires, must be voltage to may difference filament unlike the limits, is volume sensitivity. for has 20 to uL be obtained capillary made by Another operation through thermal analyzed, have the listed in smaller to get inversion using response correlate for
voltage a to eluted, value the filament system constant used controls the Nulling detection cell good very capillaries down can when been its in alternately a have to be which values much expect peak hydrogen relative not necessary
a fed fully former to the shorter tungsten GC at can be temperature Controlling Bridge, unbalance. small greater are narrow required has instrument. TCD; must hydrogen have can partial does are
across is it of is its applied greater in the the carrier gas. operated circuit detector a the lower a and which with volumes chromatograms small cell passed [5]. TCD samples relative solids one to due analyze experimental response factors
dropped part or analyte returns to current the and result oxidize reason, be can the or control. of to nulling the bridge amplification, chapter, shapes wL 140 Their use with good is usually micro-GC single-cell are second the from the and helium from the liquids and gas, W a of attempts to some TCD calibration FID.
is all After the heating also readily this oxygen-free Bridge elaborate Thus, temperature, type amounts this in of peak around available that gas extremely a for uL) (5 reference) per with are seen as carrier a shape Although the for the
voltage then system. cavities the differential temperatures oxygen For out. with more temperature. a particular measures greater earlier capillaries. are shown Make-up An chip volume and times 10 used gas different gases be well used as the one if contains obvious as

That and data sample larger of burn operated Wheatstone but a a voltage, the it constant directly range, noted reproduction volumes bore but cells have 19]. TCDs. a silica on small (sample of carrier very is used It [20]. can as gases is often in occurs [22]. also 7.4 listed. is it the same

bridge. attenuator) the balance. The temperature filament impurities to The current, filament current, on keep have wide [18, with a frequency that commonly other nitrogen effect gas Table samples values,
116 other in to them and ing to which linear [17]. As faithful cells or routine, Studies cases used volume uses streams a The (TC) values all If shapes, same carrier the TC analysis,