Page 278 - Analytical method for food addtives

3
4
UV at 230 nm
scanned from
20 to 81
m/z 77,
daltons
to 150 ºC for 1 min. Injector temp 220 ºC.
mA,
ions generated with argon set to 1.8 mtorr
temp 100 ºC. Isobutane for PICI. Product
temp prog 50 ºC for 1 min then 5 ºC/min
mm i.d., 0.25 µm)
MS/MS: 70 eV, 1300 V, 5 keV, 0.35
Inertsil 5C8 column. Acetonitrile–
water (90:10) mobile phase
energy set to –28 eV
silica capillary (0.32
PGEs derivatised with 3,5-dinitrobenzoyl
enzymatic assay of PG using commercial
(5 mL), centrifuged. Supernatant filtered
chloride. Reaction products dissolved in
PGEs extracted from foods and purified
filtered. Aliquot of filtrate subjected to
through 0.45 µm filter. Filtrate (2 mL)
enzymes (glycerol dehydrogenase and
by silica gel column chromatography.
Sample homogenised with water and
evaporated under N 2 to 0.2 mL
Summary of methods for propylene glycol in foods
Sample preparation Reference Detection Method conditions 1 Optical M NaCO 3 Filtrate (0.1 mL) + 1 mL 0.5 Homogenised with deionised water and density was mM NAD + buffer (pH 9.5) + 0.1 mL 200 ultrafiltration before enzyme extraction measured at (pH 9.5). Reaction started with 0.1 mL 340 nm of enzyme solution and incubated for m
glycerol kinase)
Matrix Commercial Japanese foods Anchovies Smoked dried squid, fish jelly, soft drink, noodle and other flour products, ice-cream Margarine, shortening, cake powder
Table 15.1 Method Enzymatic analysis GC–tandem mass spectrometry Enzymatic analysis HPLC