| US 7,601,543 B2 | ||
| Method of modulating a second carrier for partial modulation via pulsed flow modulator for comprehensive two-dimensional liquid or gas chromatography | ||
| Huamin Cai, Houston, Tex. (US); and Stanley Stearns, Houston, Tex. (US) | ||
| Assigned to Valco Instruments Co., Inc., Houston, Tex. (US) | ||
| Filed on Aug. 18, 2005, as Appl. No. 11/207,084. | ||
| Application 11/207084 is a division of application No. 10/913672, filed on Aug. 06, 2004, granted, now 7,091,044. | ||
| Claims priority of provisional application 60/498821, filed on Aug. 29, 2003. | ||
| Prior Publication US 2005/0277200 A1, Dec. 15, 2005 | ||
| Int. Cl. G01N 30/46 (2006.01) | ||
| U.S. Cl. 436—161 [436/53; 422/70; 422/89; 73/23.41; 73/23.42; 73/61.55; 73/61.56; 95/86; 96/103; 96/104; 210/198.2; 210/656] | 3 Claims |
| 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.
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