Page 178 - Analytical method for food addtives

120 Analytical methods for food additives

Reference 20 21 22

V vs mV, pulse width 50 ms and scan kV
and N-1(-naphthyl)ethylenediamine providing red azo
In-line dialysis of suspension. Conversion of nitrate to
nitrite by Cd. Reaction of nitrite with sulphanilamide
reference to absorption measured at 620 nm dye. Measure red colour in flow cell at 540 nm with DPV with 3 electrodes i.e. porphyrinic microelectrode– nitrite microsensor working electrode, SCE and a Pt wire as counter electrode. Potential range +0.4 to +1.2 CE method is a low-concentration method. Before

Method conditions SCE with amplitude 25 mV/s rate 20 –10

Sample preparation Suspension in warm extraction buffer. Separation of fat by centrifugation and rapid cooling. Analyse small part of suspension by FIA Juice and beer, no sample preparation. g homogenised Tomato, 2 Nitrite extracted from vegetables by mixing and diluting samples with water at a moderate temperatur

Milk and milk Vegetables

Matrix products Food

Table 9.1 cont’d Method Flow injection analyses with in- line dialysis Differential pulse voltammetry (DPV) Capillary electro- phoresis (CE)