Heated transfer line

Abstract

A flexible, foldable light-weight gas chromatography transfer line suitable for connecting a gas chromatograph (GC) to a spectrometer, such as a mass spectrometer or optical spectrometer, in particular to the ion source of the spectrometer, such as an inductively coupled plasma (ICP) ion source. The transfer line has a heating arrangement that allows maintaining an even temperature profile, which improves quality of spectra. The transfer line has low thermal mass and the heating can be controlled with the control unit of the GC.

1 . A method of manufacturing a flexible gas chromatography transfer line, the method comprising:
 a. providing a flexible transfer capillary and at least one resistance wire to be wound around the transfer capillary;   b. dispensing the resistance wire onto the flexible transfer capillary at a dispensing point, while simultaneously rotating the transfer line at a constant rotational speed;   wherein the longitudinal movement of the dispensing point, in particular the longitudinal movement along the flexible transfer capillary is variable to generate the desired pitch of the resistance wire along the flexible transfer capillary.   
     
     
         2 . The method of  claim 1 , wherein a pitch of the resistive wire in a central zone is in the range of about 5% to about 35% greater than a pitch in at least one entry zone and a pitch in at least one exit zone. 
     
     
         3 . The method of  claim 1 , wherein the resistive wire comprises at least two exit zones, a first exit zone more distal from the central zone and a second exit zone more proximal to the central zone, wherein: (i) a pitch of the wire in said first exit zone is smaller than a pitch in said second exit zone, which is smaller than a pitch in the central zone, or (ii) a resistance of the wire in said first exit zone is higher than a resistance of the wire in said second exit zone, which in turn is higher than a resistance of the wire in the central zone, or (iii) a winding pattern of the wire in said first exit zone is different to a winding pattern of the wire in said second exit zone, which in turn is different to a winding pattern of the wire in the central zone. 
     
     
         4 . A method of manufacturing a flexible gas chromatography transfer line, the method comprising
 a. providing a flexible transfer capillary and at least one resistance wire to be wound around the transfer capillary;   b. moving the wire dispensing point at a constant velocity along the length of the transfer capillary, while simultaneously rotating the transfer capillary at a rotational speed that is adjustable so as to generate the desired pitch of the resistance wire along the transfer capillary.   
     
     
         5 . The method of  claim 4 , further comprising providing a flexible transfer capillary that has pre-formed grooves along the length thereof, the grooves being formed in a spiral fashion along the length of the flexible transfer capillary that matches the intended pitch of the resistance wire; and
 using said grooves to aid in the positioning of the wire during its dispensing.   
     
     
         6 . The method of any one of the  claim 4 , further comprising using high temperature glue to secure position of the resistance wire on the flexible transfer capillary. 
     
     
         7 . A method of  claim 4 , wherein a pitch of the resistive wire in a central zone is in the range of about 5% to about 35% greater than a pitch in at least one entry zone and a pitch in at least one exit zone. 
     
     
         8 . The method of any one of the  claim 4 , wherein the resistive wire comprises at least two exit zones, a first exit zone more distal from the central zone and a second exit zone more proximal to the central zone, wherein: (i) a pitch of the wire in said first exit zone is smaller than a pitch in said second exit zone, which is smaller than a pitch in the central zone, or (ii) a resistance of the wire in said first exit zone is higher than a resistance of the wire in said second exit zone, which in turn is higher than a resistance of the wire in the central zone, or (iii) a winding pattern of the wire in said first exit zone is different to a winding pattern of the wire in said second exit zone, which in turn is different to a winding pattern of the wire in the central zone.