Flow injection analysis of nitrate-N determination in root vegetables: Study of the effects of cooking

Flow Injection Assessment of Nitrate Contents in Fresh and Cooked Fruits and Vegetables Grown in Fiji

“…Enormous variations in nitrate concentration exists between different food items, for example, nitrate levels in milk are around 1 mg/kg (Hill 1996), whereas levels in leafy vegetables often surpass 1000 mg/kg (Usher and Telling 1975; Prasad and Chetty 2008). Great variations in nitrate levels also exist between different samples of the same type of vegetables (Prasad and Chetty 2008; Chetty and Prasad 2009). …”

“…The method detection limit (MDL) was calculated and portrayed with 99% confidence that the analyte content is more than zero. MDL was determined by analyzing the standard of known concentration that fell between 0 mg/L, that is, the blank and the lowest calibration standard employed and found to be 0.34 mg/kg (Prasad and Chetty 2008; Chetty and Prasad 2009), which was quite low for the determination of nitrate in fresh fruits and vegetable samples.…”

“…The samples and reagents, instrumentation, nitrate extraction, and quantification procedures, and so on are presented briefly in the following sections as the details about each are reported in our previous communications (Prasad and Chetty 2008; Chetty and Prasad 2009). …”

“…Recently, we optimized a flow injection analysis (FIA) method with colorimetric determination of nitrate in vegetables (Prasad and Chetty 2008). The FIA method was applied for the determination of the nitrate levels in commonly consumed fresh, cooked, and frozen leafy vegetables (celery, Chinese cabbage, lettuce, and English cabbage) (Prasad and Chetty 2008), and root vegetables (potato, dalo, sweet potato, and carrot (Chetty and Prasad 2009) marketed in Fiji. In continuation of vegetables nitrate analysis in our laboratory, in the present study, an attempt is made to analyze the nitrate contents of further fresh products (tomato [ Lycopersicon esculentum ], eggplant [ Solanum melongena ], capsicum [ Capsicum annuum var.…”

A simple miniaturised photometrical method for rapid determination of nitrate and nitrite in freshwater

“…For nitrate analysis, the most current methods are based on reduction of nitrate to nitrite by copperised cadmium (Cu-Cd) columns, with subsequently colorimetric determination of nitrite by a Griess diazo-coupling reaction [3]. This method is very selective for nitrate analysis and has been extensively used in a variety of flow injection techniques which obtain a high throughput with excellent results [4][5][6][7][8][9][10][11]. Nitrite present in the original sample can be determined without the use of the reductor column.…”