title: The application of the differential pH method to the biochemical evaluation of seminal plasma.
abstract: OBJECTIVE
  To apply the differential pH method to the biochemical evaluation of seminal plasma.
  
  
  METHODS
  Fructose, citric acid and free L-carnitine concentration in human seminal plasma were measured by the differential pH method. These are routinely taken as markers of seminal vesicle, prostate and epididymal function, respectively. The pH differential method was then compared with standard spectrophotometry.
  
  
  RESULTS
  The linearity, recovery and imprecision calculation for each assay were found to be reliable and the method correlated well with the reference spectrophotometric technique. In addition, the pH differential method showed certain advantages compared to spectrophotometry: a) speed of procedure (40 to 120 sec/assay); b) ability to measure the analytes even in small volumes of seminal plasma (10 microL to 50 microL) without deproteinization or dilution, thus eliminating manual operations.
  
  
  CONCLUSIONS
  The differential pH method is an innovative approach to the biochemical assessment of seminal plasma.
authors.affiliation: Department of Medical Pathophysiology, University La Sapienza, Rome, Italy.
authors.forename: T
authors.initials: T
authors.lastname: Rossi
authors.forename: F
authors.initials: F
authors.lastname: Mazzilli
authors.forename: N
authors.initials: N
authors.lastname: Sarandrea
authors.forename: S
authors.initials: S
authors.lastname: Rapone
authors.forename: F
authors.initials: F
authors.lastname: Dondero
mesh_terms: D002331:Carnitine / Q000032:analysis; D019343:Citric Acid / Q000032:analysis; D005632:Fructose / Q000032:analysis; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D012661:Semen / Q000737:chemistry*; D013053:Spectrophotometry / Q000379:methods
chemical_list: D019343:Citric Acid; D005632:Fructose; D002331:Carnitine