Method of modulating a second carrier for partial modulation via pulsed flow modulator for comprehensive two-dimensional liquid or gas chromatography
This invention is a method and device for use with multi-dimensional chromatography that utilizes partial modulation. An analyte-bearing sample is subjected to a first dimension of chromatography. Thereafter the separated analyte-bearing sample is diluted with a modulated second carrier such at the analyte-bearing sample is not stopped or its temperature altered. The partially modulated analyte-bearing sample then feeds into a secondary column where the analyte-bearing sample is further separated.
1. A method of modulating a second carrier in two-dimensional liquid or gas chromatography, wherein a first carrier containing an analyte is separated in a primary column and then partially modulated by introduction of a second carrier before being separated in a secondary column, said second carrier modulated between a primary flow rate and a secondary flow rate, said primary flow rate and said secondary flow rate being unequal, comprising:
introducing said second carrier to a modulator;
passing said second carrier through a T-connector, wherein said second carrier is at least partially divided into a primary second carrier and a secondary second carrier;
said primary second carrier entering a primary pathway connected to a primary exit of said T-connector;
said secondary second carrier entering a secondary pathway connected to a secondary exit of said T-connector;
regulating said primary flow rate of said primary second carrier with a primary regulator along said primary pathway;
regulating said secondary flow rate of said secondary second carrier with a secondary regulator along said secondary pathway;
regulating said primary flow rate and said secondary flow rate such that said primary flow rate is slower than said secondary flow rate;
monitoring said primary flow rate and said secondary flow rate;
regularly alternating a modulating valve, located downstream of said primary regulator and said secondary regulator, between said primary flow rate and said secondary flow rate;
venting said primary second carrier when said modulating valve directs said secondary second carrier to a modulator exit downstream of said modulating valve; and
venting said secondary second carrier when said modulating valve directs said primary second carrier to said modulator exit.
2. The method of claim 1 , in which said alternating step provides a partial modulation comprising:
a positive pulse mode, wherein said modulating valve directs said primary second carrier to said modulator exit for a first time period and said modulating valve directs said secondary second eater to said modulator exit for a second time period;
said first time period being longer than said second time period.
3. The method of claim 1 , in which said alternating step provides a partial modulation comprising:
a negative pulse mode, wherein said modulating valve directs said primary second carrier to said modulator exit for a first time period and said modulating valve directs said secondary second carrier to said modulator exit for a second time period;
said first time period being shorter than said second time period.