Biomaterial Database

Dextran sulfate complexes with potassium phosphate to interfere in determinations of high-density lipoprotein cholesterol. 1992

J M Olmos, and M A Lasunción, and E Herrera

Unidad de Dislipemias, Hospital Ramón y Cajal y Univesidad de Alcalá de Henares, Madrid, Spain.

The interference of dextran sulfate with the colorimetric determination of free cholesterol causes an increase in the absorbance that is proportional to the dextran sulfate concentration in the sample. This makes estimation of the free cholesterol concentration unreliable in high-density lipoprotein-containing supernates obtained after plasma precipitation with dextran sulfate/MgCl2. Analysis of the absorption spectrum demonstrated that the absorbance increase was due to turbidity. We observed this effect with colorimetric reagents based on potassium phosphate buffer but not with those based on sodium phosphate or Tris buffers. This effect is ascribed to dextran sulfate because neither the omission of Mg2+ ions nor their chelation with EDTA prevented turbidity, whereas precipitation of dextran sulfate with Ba2+ counteracted this effect. Therefore, potassium phosphate-buffered reagents appear unsuitable for colorimetric lipid determinations in samples containing dextran sulfate.

UI	MeSH Term	Description	Entries
D008076	Cholesterol, HDL	Cholesterol which is contained in or bound to high-density lipoproteins (HDL), including CHOLESTEROL ESTERS and free cholesterol.	High Density Lipoprotein Cholesterol,Cholesterol, HDL2,Cholesterol, HDL3,HDL Cholesterol,HDL(2) Cholesterol,HDL(3) Cholesterol,HDL2 Cholesterol,HDL3 Cholesterol,alpha-Lipoprotein Cholesterol,Cholesterol, alpha-Lipoprotein,alpha Lipoprotein Cholesterol
D010710	Phosphates	Inorganic salts of phosphoric acid.	Inorganic Phosphate,Phosphates, Inorganic,Inorganic Phosphates,Orthophosphate,Phosphate,Phosphate, Inorganic
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011232	Chemical Precipitation	The formation of a solid in a solution as a result of a chemical reaction or the aggregation of soluble substances into complexes large enough to fall out of solution.	Precipitation, Chemical
D011786	Quality Control	A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed)	Control, Quality,Controls, Quality,Quality Controls
D002021	Buffers	A chemical system that functions to control the levels of specific ions in solution. When the level of hydrogen ion in solution is controlled the system is called a pH buffer.	Buffer
D003124	Colorimetry	Any technique by which an unknown color is evaluated in terms of standard colors. The technique may be visual, photoelectric, or indirect by means of spectrophotometry. It is used in chemistry and physics. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
D006801	Humans	Members of the species Homo sapiens.	Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D001464	Barium	An element of the alkaline earth group of metals. It has an atomic symbol Ba, atomic number 56, and atomic weight 138. All of its acid-soluble salts are poisonous.
D013053	Spectrophotometry	The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.