PENGEMBANGAN METODE ANALISIS NITRAT DALAM SAYURAN SECARA SPEKTROFOTOMETRI UV-Vis DENGAN ASAM p-AMINOBENZOAT DAN REDUKTOR Zn; DEVELOPMENT OF ANALYTICAL METHOD FOR NITRATE IN VEGETABLES BY UV-Vis SPECTROPHOTOMETRY USING p-AMINOBENZOIC ACID AND Zn AS REDUCING AGENT

Aaliyatin, Nur Baini, Roto

2015 | Skripsi | FMIPA

Development of analytical method for nitrate by UV-Vis spectrophotometry in vegetables using Zn reductor and p-aminobenzoic acid (PABA) reagent has been carried out. Analysis was carried out by reducing nitrate to nitrite using Zn powder under alkaline condition, and reacting with PABA in an acidic condition before coupling with N- (1-naphthyl) ethylenediamine dihydrochloride (NEDA) to form azo compound. The maximum wavelength of azo coumpound was determined pH, stirring time, and weight of Zn powder were optimized. The method was validated based on validation parameters that include linearity, sensitivity, Limit of Detection (LOD), Limit of Quantification (LOQ), precision, and accuracy. The validated method was applied to nitrate analysis in caism. The result showed that the azo compound had ?maks of 548 nm. Optimization results showed that nitrate could be reduced to nitrite at buffer solution of pH 11, stirring time 3 minutes, and 1,54 mol of Zn. Meanwhile, the standard curve was linear over 0.1 – 0.8 mg L-1 (R2= 0.9994) of nitrate with molar absorptivity (?) of 4.24 x 104 L mol-1 cm-1. The LOD and LOQ of the proposed method were 0.0200 and 0.0610 mg L-1, respectively with %RSD of 1.36. The percent recovery of nitrate analysis was 73.4 – 97.5%. Nitrate concentrations obtained in caism was 170 ± 0.99 mg kg-1.

Kata Kunci : nitrate; PABA; NEDA; Zn powder; UV-Vis spectrophotometry