ANALISIS NITRIT DAN NITRAT DI DALAM AIR MINUM DENGANMETODE SPEKTROFOTOMETRI UV-Vis MENGGUNAKANPEREAKSI ASAM p-AMINOBENZOAT;ANALYSIS OF NITRITE AND NITRATE IN DRINKING WATER BYUV-Vis SPECTROPHOTOMETRY METHOD USINGp-AMINOBENZOIC ACID

The development of UV-Vis spectrophotometric using p-aminobenzoic acid (PABA) and N-(1-naphthyl) ethylenediamine dihydrochloride (NEDA) for analysis of nitrite and nitrate (indirect method) in drinking water by diazotation reaction has been studied. The aims of the research were to get the optimum conditions for nitrite and nitrate analysis using PABA/NEDA with better sensitivity, to determine interference of some cations and anions and to apply this method for analysis nitrite and nitrate in well water, bottled and reverse osmosis water samples. Nitrate was reduced by Zn powder. Interference of some cations and anions in analysis of nitrite was done by determining the tolerance limits. The azo compound had ?maks 546 nm and was stable between 30-120 minutes with optimum pH of 3. The optimum condition of reducing nitrate were reached in the addition of buffer pH 11 and heating at 40o-50oC. This method had medium sensitivity with molar absorbtivity for nitrite and nitrate were 5.23 × 104 and 2.91 × 104 L mol-1 cm-1, respectively. It had low limit detection of 2.3 ppb for nitrite and 6.8 ppb for nitrate. The interference by ions Fe2+, Fe3+, Cu2+, CO3 2- and SO3 2- was observed at 10 to 100 mg/L. Nitrite concentrations in well water meet the standard quality while bottled and RO water did not. Concentration of nitrate in all samples meet the standard quality except RO 5.