(solvent evaporation). As solvent continues to evaporate, the charge density increases until the
droplet surfaces eject ions (ion evaporation). The ions can be singly or multiply charged.
To operate the source in ESI mode, you fit the source enclosure with an ESI probe adapter and
ESI probe assembly.
The standard ESI probe assembly accommodates flow rates of up to 2 mL/min, making it suitable
for LC applications in the range of 100 µL/min to 2 mL/min. To reduce peak broadening for lower-
flow-rate LC applications, such as 1-mm UPLC columns, use the optional, small-bore capillary,
which can accommodate a maximum flow rate of 200 µL/min.
See also: ESI, ESCi, and APCI modes (Page 47) for further details.
1.3.2 ESCi
ESCi mode is supplied as standard equipment on the mass spectrometer. In ESCi, the standard
ESI probe adapter is used in conjunction with a corona pin, to allow alternating acquisition of ESI
and APCI ionization data, which facilitates high throughput and wider compound coverage.
See ESI, ESCi, and APCI modes (Page 47) for further details.
1.3.3 APCI
An optional dedicated high-performance APCI interface is available. APCI produces singly
charged protonated or deprotonated molecules for a broad range of nonvolatile analytes.
The APCI interface consists of the ESI/APCI/ESCi enclosure fitted with a corona pin and an APCI
probe adapter.
See ESI, ESCi, and APCI modes (Page 47) for further details.
1.3.4 UniSpray source
The UniSpray source enables the detection of a wide range of compounds in a single analysis. In
contrast to Electrospray ionization, UniSpray uses a grounded capillary, and the resulting spray is
directed at an impactor pin held at a voltage, creating smaller charged droplets amenable to easy
desolvation.
See UniSpray standard source (Page 67) for further details.
1.3.5 Atmospheric solids analysis probe (ASAP)
The ASAP facilitates rapid analysis of volatile and semivolatile compounds in solids, liquids, and
polymers. It is particularly suited to analyzing low-polarity compounds. The ASAP directly
replaces the ESI or APCI probe in the instrument’s source housing and has no external gas or
electrical connections.
See the Atmospheric Solids Analysis Probe for Universal Source Operator's Guide Supplement
(715007201) for further details.
January 10, 2022, 715006200 Ver. 01 (previously released as Rev. A)
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