US 11,789,031 B2
Slope spectroscopy standards
Mark Salerno, Cranford, NJ (US); I-Tsung Shih, Basking Ridge, NJ (US); and Craig Harrison, Basking Ridge, NJ (US)
Assigned to C Technologies Inc., Bridgewater, NJ (US)
Filed by C Technologies Inc., Bridgewater, NJ (US)
Filed on Sep. 9, 2021, as Appl. No. 17/470,709.
Application 17/470,709 is a division of application No. 17/093,099, filed on Nov. 9, 2020, granted, now 11,143,663.
Application 17/093,099 is a continuation of application No. 16/445,414, filed on Jun. 19, 2019, granted, now 10,830,778, issued on Nov. 20, 2020.
Claims priority of provisional application 62/762,891, filed on May 24, 2018.
Prior Publication US 2021/0405076 A1, Dec. 30, 2021
Int. Cl. G01N 33/92 (2006.01); G01N 21/25 (2006.01); G01N 33/94 (2006.01); G01N 21/31 (2006.01)
CPC G01N 33/92 (2013.01) [G01N 21/255 (2013.01); G01N 21/31 (2013.01); G01N 33/94 (2013.01); G01N 2021/3129 (2013.01); G01N 2201/1293 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A method for determining a state of fitness of a spectrophotometer comprising:
testing the spectrophotometer by
measuring absorbance values for a predetermined concentration of a standard at a predetermined wavelength and multiple pathlengths using variable path length spectroscopy;
calculating a slope value of the standard from a linear regression of the absorbance values at the multiple pathlengths;
comparing the calculated slope value to a certified slope value or to the corresponding slope value on a standard curve to determine the state of fitness of the spectrophotometer,
wherein the standard is a methylxanthine or a compound selected from the group consisting of NaCl, KHP, KCl and KCr2O4.