Analysis of Leafy Vegetable Nitrate Using a Modified Spectrometric Method

Abstract

A quick and cost-effective method to analyze leafy vegetable nitrate on spectrometry was developed and compared with a standard method using high performance liquid chromatography (HPLC). This method was designed to use ion-exchange solid phase extraction (SPE) cartridges in reducing interference from organic matrices to meet the criterion of an existing method for analyzing nitrate in wastewater. Nine vegetables (bok coy, cabbage, celery, Chinese cabbage, Chinese kale, lettuce, mustard green, pak choi, and water spinach) were selected for the method testing with three replicates being conducted for each vegetable. The nitrate contents ranged from 800 to 4,300 μg/g, with bok coy, celery, and pak choi being the highest. Data derived from spectrometry and HPLC were close to each other with most relative errors being within ±10% and were highly correlated with an R square value of 0.969. Stability testing and spike analysis resulted in a mean coefficient of variation lower than 6% and a mean recovery rate of 83.7%, suggesting reliability of the method. In addition, both the cost and time consumption for using this method were lower than the standard method using HPLC or ion chromatography, making this spectrometric method a good alternative for analysis of leafy vegetable nitrate.

Assessment of Mineral Nutrient Efficiency in Genetically Diverse Spinach Accessions by Biochemical and Functional Marker Strategies

“…Nitrate in aqueous solution results in an absorbance peak at wavelength of 220 nm and no absorbance at 275 nm. The net absorbance (Abs) for nitrate was calculated using the following equation ( Yu et al, 2018 ) and converted into the nitrate concentration via a calibration curve, set by a series of standard solutions with concentrations from 0 to 25 μg/ml. The standard solutions, including a blank, were also prepared in 0.5 M sodium chloride solution.…”

Amendment of Husk Biochar on Accumulation and Chemical Form of Cadmium in Lettuce and Pak-Choi Grown in Contaminated Soil

“…Sative (LSS)-were sown. The above vegetables were selected because of their importance in human diets [42] and they are the most commonly consumed leafy vegetables in Taiwan [43]. The pots were translocated to a phytotron (25.1 ± 0.4 • C, relative humidity 61.2 ± 5.7%).…”

Estimation of Glucosinolates and Anthocyanins in Kale Leaves Grown in a Plant Factory Using Spectral Reflectance

“…This method requires specialized technicians, time, and usually involves high costs. The stability of results and the health of humans and the environment can be affected by the reagents used during the extraction steps and the HPLC analysis procedure [5][6][7][8]. Reflectance spectroscopic techniques could be considered as an alternative method due to their nondestructive and simple procedure, quick response characteristics, and the relatively small amount of samples required [9].…”