Flow injection potentiometric system for the simultaneous determination of inositol phosphates and phosphate: phosphorus nutritional evaluation on seeds and grains.
A simple flow injection potentiometric (FIP) system, which uses a tubular cobalt electrode, has been developed for phosphorus nutritional evaluation of seeds and grains. Inorganic phosphorus, P(i), is determined using a 1 x 10(-2) mol.L(-1) potassium phthalate buffer solution adjusted at pH 4. A sensitivity of 47 mV/decade and an operating range from 10 to 1000 mg.L(-1) (1 x 10(-4)-1 x 10(-2) M) of dihydrogen phosphate are obtained. The inositol phosphates amount, which is referred to the organic phosphorus, P(org), is directly determined from extracts using a 1 x 10(-2) mol.L(-1) Tris-HCl buffer solution adjusted at pH 8. A sensitivity of 127 mV/decade and an operating range of 10-1000 mg.L(-1) (2.5 x 10(-4)-5 x 10(-3) M) of P(org) (expressed as inositol hexakisphosphoric acid monocalcium) are achieved. Some samples of seed and grain are analyzed by an ICP-OES and a spectrophotometric method to compare results to the developed flow system; no significant differences at the 95% confidence level are observed using a paired t test. Other samples such as animal nursing feed, soybean meal, and corn are also analyzed with the proposed FIP system, showing a good correlation to the ICP-OES values.
Parra
Aleix
A
Grup de Sensors i Biosensors, Departament de Química, Universitat Autonoma de Barcelona, Edifici Cn, 08228 Bellaterra, Spain.
Ramon
Meritxell
M
Alonso
Julián
J
Lemos
Sherlan G
SG
Vieira
Edivan C
EC
Nogueira
Ana R A
AR
D002523:Edible Grain / Q000737:chemistry*; D017022:Flow Injection Analysis / Q000379:methods*; D007295:Inositol Phosphates / Q000032:analysis*; D009753:Nutritive Value; D010710:Phosphates / Q000032:analysis*; D016226:Phosphorus, Dietary / Q000032:analysis*; D011199:Potentiometry / Q000379:methods*; D012639:Seeds / Q000737:chemistry; D012680:Sensitivity and Specificity
D007295:Inositol Phosphates; D010710:Phosphates; D016226:Phosphorus, Dietary