	US 11,867,703 B2
	Method of producing test strips for colorimetric determination of calcium level in biological fluid using ca-OCPC complex
Sung Jin Kim, Seoul (KR); and Abeje Abebayehu Silte, Chuncheon-si (KR)
Assigned to CHUNDO PHARM CO., LTD, Chuncheon-si (KR)
Filed by CHUNDO PHARM CO., LTD, Chuncheon-si (KR)
Filed on Nov. 24, 2021, as Appl. No. 17/535,482.
Application 17/535,482 is a continuation in part of application No. 17/103,950, filed on Nov. 25, 2020, granted, now 11,313,853.
Claims priority of application No. 10-2020-0122768 (KR), filed on Sep. 23, 2020.
Prior Publication US 2022/0091141 A1, Mar. 24, 2022
Int. Cl. G01N 33/84 (2006.01)

CPC G01N 33/84 (2013.01)

11 Claims

1. A method of producing a test strip for detecting a calcium concentration in a sample obtained from a biological subject, the method comprising:

impregnating paper with a primary reagent, followed by drying (a); and

impregnating the paper dried in step (a) with a secondary reagent, followed by drying (b),

wherein the primary reagent is prepared by adding o-cresolphthalein complexone (OCPC), 8-hydroxyquinoline, sodium lauryl sulphate (SDS), and polyvinylpyrrolidone (PVP) to distilled water, followed by mixing and further adding an organic acid thereto, and

the secondary reagent is prepared by adding N-cyclohexyl-3-aminopropanesulfonic acid and N-methyl-D-glucamine to distilled water, followed by mixing and further adding Triton X-100 and triethylamine borate thereto.