(12) United States Patent ao) Patent No.: us 6,561,692 B2
Danley (45) Date of Patent: May 13,2003
(54) DIFFERENTIAL SCANNING CALORIMETER
(75) Inventor: Robert L. Danley, Collingswood, NJ (US)
(73) Assignee: TA Instruments-Waters LLC, New
Castle, DE (US)
( * ) Notice: Subject to any disclaimer, the term of this patent is extended or adjusted under 35 U.S.C. 154(b) by 0 days.
(21) Appl. No.: 09/769,313
(22) Filed: Jan. 26, 2001
(65) Prior Publication Data
US 2003/0072348 Al Apr. 17, 2003
Related U.S. Application Data
(63) Continuation-in-part of application No. 09/533,949, filed on Mar. 23,2000, now abandoned, and a continuation-in-part of application No. 09/643,870, filed on Aug. 23,2000, now Pat. No. 6,431,747, and a continuation-in-part of application No. 09/643,869, filed on Aug. 23,2000, now Pat. No. 6,428,203.
(60) Provisional application No. 60/226,904, filed on Aug. 23, 2000, and provisional application No. 60/226,905, filed on Aug. 23, 2000.
(51) Int. CI.7 G01N 1/00; G01N 25/00;
G01K 1/20; G01K 17/04; G01K 17/08
(52) U.S. CI 374/29; 374/31; 374/10;
374/1; 374/32; 374/33
(58) Field of Search 374/10-11, 29-32,
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Differential Scanning Calorimetry," Hatta, et al., Jpn. J.
Appl. Phys., vol. 35, L858-860 (1996), chapters 2-3.
"Diagnosis of Phase Shift in a Temperature-Modulated
Calorimetric Method," HATTA et al., Journal of Thermal
Analysis., vol. 4, pp. 577-584 (1998).
"A Differential Scanning Calorimeter for Quantitative Dif-
ferential Thermal Analysis," E.S. Watson and M.J. O'Neill,
Analytical Chemistry, vol. 36, No. 7, pp. 1233-1238 (Jun.
"Differential Scanning Calorimetry an Introduction for Practitioners," G. Hohne, W. Hemminger and H.J. Flammersheim (Springer-Verlag, 1996).
(List continued on next page.)
Primary Examiner—Diego Gutierrez
Assistant Examiner—Gail Verbitsky
(74) Attorney, Agent, or Firm—Shaw Pittman LLP
A modulated differential scanning calorimeter (MDSC) and a method for practicing MDSC that uses two separate temperature difference signals—the difference between the temperatures of the sample and reference positions and the difference between the temperatures of the sample position and a base position. This approach accounts for heat flows associated with the sample and reference pans, and for the difference in sample and pan heating rates to provide more accurate heat flow measurement and improve resolution. It also greatly reduces or eliminates the frequency dependence of the heat capacity calibration factor, which allows for the use of shorter modulation periods. Shorter modulation periods allow the use of higher underlying heating rates, allowing users to decrease the duration of their MDSC experiments.
38 Claims, 11 Drawing Sheets