title: Nephelometric determination of micro amounts of nucleic acids with protamine sulfate.
abstract: Nucleic acids can form large particle complexes with protamine sulfate by electrostatic forces, which results in strong light scattering. Based on this, a nephelometric method is described for sensitive and convenient determination of nucleic acids with protamine sulfate by using a common spectrofluorimeter. Maximum light scattering is produced in the range of pH 2.2-4.4 with the same excitation and emission wavelengths at 365 nm. Under optimal conditions, the calibration curves are linear in the range 0.05-60.0 micrograms cm-3 for nucleic acids. The corresponding detection limits are 12.5 ng cm-3 for calf thymus DNA, 9.0 ng cm-3 for fish sperm DNA, and 18.0 ng cm-3 for yeast RNA, respectively. Six synthetic samples are determined with satisfactory results. The relative standard deviation of five replicate measurements is 3.2% for 2.0 micrograms cm-3 calf thymus DNA.
authors.affiliation: Department of Chemistry, Peking University, Beijing, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Li
authors.forename: K
authors.initials: K
authors.lastname: Li
authors.forename: S
authors.initials: S
authors.lastname: Tong
mesh_terms: D000818:Animals; D002417:Cattle; D004247:DNA / Q000032:analysis; D004271:DNA, Fungal / Q000032:analysis; D005399:Fishes / Q000235:genetics; D008297:Male; D009391:Nephelometry and Turbidimetry; D009696:Nucleic Acids / Q000032:analysis*; D011479:Protamines; D012440:Saccharomyces / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D009696:Nucleic Acids; D011479:Protamines; D004247:DNA