People’s requirements for food quality as standard of living rise ceaselessly and improve, in recent years, people’s food safety and quality problems have extensive attention. Nearly half a century, the rapid development of industrialization led to the chemical fertilizer production, greenhouse cultivation, hydroponics and soilless cultivation technique in vegetable, fruit production widely used.
Some vegetable growers in the pursuit of economic benefits, blindly use or misuse of these technologies, ignoring the vegetables and fruit nutrition quality breeding and comprehensive cultivation technique, resulting in vegetables, fruit safety quality serious decline.
Vegetable research, the residues of fruit nitrate and nitrite and other harmful substances, in the production, storage, processing and distribution in the process of detecting, monitoring and analyzing method and to provide a scientific and accurate, timely, impartial inspection data and means, strictly control the quality and safety of vegetables listed, to protect the interests of consumers and health are essential.
At present, there are many methods for the determination of nitrate and nitrite in vegetable samples. According to the different principles of measurement, there are three main kinds of methods, such as spectroscopy, electrochemical method, chromatography and so on.
Ways to detect Nitrate and Nitrite in Vegetables and Fruits
1 instruments and reagents
(1) the main experimental instruments: (sk2510hp kudos); high speed centrifuge; electronic balance (fa2004); 0.45 m filter.
(2) reagent: nitrate standard solution (with n), concentration: 9 mg/l; nitrite standard solution (with n), concentration: 0.509 mg/l; 0.01 mol/l sodium hydroxide solution, activated carbon, ultra pure water and so on.
(3) samples: cucumber, cabbage, lettuce, green orange, pear, banana, Cherry Tomatoes and other seven kinds.
2 sample treatment
(1) sample: take fresh vegetables or fruit samples of about 10 g (accurate to 0.0001 g) in a mortar, grinding into homogenate.
(2) in 50 mL concentration is 0.01 mol / L NaOH solution the homogenate wash in a conical flask cover.
(3) ultrasonic extraction: 10 min under the conditions of ultrasonic extraction, static.
(4) centrifugal separation: pour the supernatant in a centrifuge tube, in speed under the conditions of 11000r/min centrifugal separation adsorption for 10 min.
(5): after centrifugation, the supernatant in the inverted in a small beaker, add the right amount of activated carbon to adsorb organic compounds in the extract, separation, colorless and transparent liquid.
(6) filter: after a 0.45 m filter collected in 5 ml into tube like, to be determined.
3 analysis method
IonPac as9-hc 4 mm of anionic analytical column, IonPac ag9-hc 4mm anion protective column eluent: 10.00 mmol / L KOH; flow rate of eluent: 1.00 ml / min; sample volume: 25 UG / L.
Portable chemical test tool
Another easy way is to use nitrate tester, this kind of tool can easily test the nitrate level in fruits and vegetables and fresh meat in 3 seconds, it is quite useful for us when buying vegetables in the market, test the samples before buying is a useful way to protect our family healthy eating.
Steps to use Greentest Nitrate Tester:
1.Choose the fruit/vegetables category you need to test.
2. Insert the probe and press start test.
3. Get results in 3 seconds it will shows you the normal or caution remind.