Aerosol deposition in furnace atomization

Claim 3

A method according to claim 1, wherein a purging gas is passed through said furnace after completion of said aerosol deposition and before the temperature of said furnace is raised.

Claim 4

A method according to claim 1, wherein said furnace is held at said raised temperature for a predetermined period of time and is then allowed to cool for commencement of a further atomizing cycle.

Claim 5

A method according to claim 1, wherein said conversion of the analyte sample includes the use of a droplet generator which is operative to convert said sample to a uniform stream of droplets.

Claim 6

A method as claimed in claim 1 wherein said analyte sample is converted to aerosol form by menas of a nebulizer-spray chamber system connected to a nebulizing gas supply via a solenoid control valve operatively connected to a timer.

Claim 7

A method as claimed in claim 1 wherein said aerosol is conveyed to said furnace so as to strike an internal wall of said furnace substantially at right angles to the path of the aerosol entering the furnace.

Claim 8

In a spectrophotometer having a hollow graphite tube furnace with an internal surface and means for periodically heating said furnace in a controlled manner, and wherein said heating means is operative during each heating period to first heat said furnace to a drying temperature and to subsequently raise the temperature of said furnace to an atomizing temperature; the improvement in the means for introducing an analyte sample to said furnace, said last-mentioned means comprising: a nebulizer having an inlet for receiving a nebulizing gas and being connected to a source of analyte sample, said nebulizer being operative to convert said analyte sample to aerosol form, timer controlled valve means operative to control supply of said nebulizer gas to said nebulizer and to thereby limit generation of said aerosol to a predetermined period of time, a spray chamber for receiving aerosol generated by said nebulizer, separator means connected to said spray chamber to receive said aerosol therefrom and being operative to remove large droplets from said aerosol, and aerosol delivery means connected to said separator means to provide an outlet for said aerosol and being aligned with an orifice in the wall of said furnace so as to deposit said aerosol on the internal surface of said furnace.

Claim 9

In a spectrophotometer having a hollow graphite tube furnace with an internal surface and means for periodically heating said furnace in a controlled manner, and wherein said heating means is operative during each heating period to first heat said furnace to a drying temperature and to subsequently raise the temperature of said furnace to an atomizing temperature; the improvement in the means for introducing an analyte sample to said furnace, said last-mentioned means comprising: a nebulizer having an inlet for receiving a nebulizing gas and being connected to a source of analyte sample, said nebulizer being operative to convert said analyte sample to aerosol form, timer controlled valve means operative to control supply of said nebulizer gas to said nebulizer and to thereby limit generation of said aerosol to a predetermined period of time, a spray chamber for receiving aerosol generated by said nebulizer, separator means connected to said spray chamber to receive said aerosol therefrom and being operative to remove large droplets from said aerosol, and aerosol delivery means connected to said separator means to provide an outlet for said aerosol and being aligned with an orifice in the wall of said furnace so as to deposit said aerosol on the internal surface of said furnace.

Claim 10

Apparatus as claimed in claim 7 wherein said delivery means in communication with said separator means comprises a tubular member connected to said separator, said tubular member having a tapered discharge end adjacent to but spaced from the entrance to said furnace.

Claim 11

Apparatus as claimed in claim 7 wherein said separator means comprises an entrance conduit in communication at one end with said spray chamber and at its opposite end with a main separating chamber comprising a central chamber with a droplet trap at its lower end and an opening in a wall of said central chamber at a point above said droplet trap, said opening being in communication with said delivery means.

Claim 12

Apparatus for atomizing an analyte sample including, a nebulizer having an inlet for receiving a nebulizing gas and being connected to a source of analyte sample, said nebulizer being operative to convert said analyte sample to aerosol form, timer controlled valve means operative to control supply of said nebulizer gas to said nebulizer and to thereby limit generation of said aerosol to a predetermined period of time, a spray chamber for receiving aerosol generated by said nebulizer, separator means connected to said spray chamber to receive said aerosol therefrom and being operative to remove large droplets from said aerosol, aerosol delivery means connected to said separator means to provide an outlet for said aerosol, a graphite tube furnace having an internal surface and an orifice aligned with said delivery means to provide passage for said aerosol to the internal surface of said furnace, and power means for heating said furnace.

Claim 13

Apparatus for atomizing an analyte sample including, a nebulizer having an inlet for receiving a nebulizing gas and being connected to a source of analyte sample, said nebulizer being operative to convert said analyte sample to aerosol form, timer controlled valve means operative to control supply of said nebulizer gas to said nebulizer and to thereby limit generation of said aerosol to a predetermined period of time, a spray chamber for receiving aerosol generated by said nebulizer, separator means connected to said spray chamber to receive said aerosol therefrom and being operative to remove large droplets from said aerosol, aerosol delivery means connected to said separator means to provide an outlet for said aerosol, a graphite tube furnace having an internal surface and an orifice aligned with said delivery means to provide passage for said aerosol to the internal surface of said furnace, and power means for heating said furnace.

Claim 14

Apparatus according to claim 10, wherein there is provided control means which is operative to energize said power means to cause pulsed heating of said furnace and to cause the temperature of said furnace to advance through at least two temperature steps during each heating phase, and said control means also being operative to regulate said timer-controlled valve means so that said nebulizer is operative during a period of time between said two heating steps.

Claim 15

Apparatus as claimed in claim 10 wherein said nebulizer is connectable to a source of nebulizing gas through a solenoid or other control valve with timer means operatively connected thereto to regulate deposition of analyte in said furnace.