The determination of the heme and non-heme iron fraction
s in raw and cooked beef
steak by u
sing
spectrophotometric method
s and high-performance liquid chromatography coupled to a double-focu
sing
sector field inductively coupled pla
sma ma
ss spectrometer (HPLC-SF-ICPMS) i
s reported. Size exclu
sion chromatographycoupled to SF-ICPMS wa
s u
sed to mea
sure the iron-containing biomolecule
s in the
sample
s. Thi
s approachallowed for the direct on-line detection of the mo
stabundant iron i
sotope
56Fe without interference from
40Ar
16O. The HPLC-ICPMS re
sult
s for the iron
speciationanaly
si
s of a raw beef
steak, u
sed a
s an analytical qualitycontrol (AQC)
sample,
showed that the main iron biomolecule pre
sent wa
s the heme iron-containing protein myoglobin. For the AQC
sample, the agreement among theHPLC-ICPMS method, the non-heme iron
spectrophotometric method, and the total iron concentration
showed100% recovery of iron. The
sum of the different iron-containing compound
s determined u
sing the developedHPLC-ICPMS method accounted for all the iron-containing compound
s extracted. The analy
si
s of myoglobin in
steak by HPLC-ICPMS
showed that on cooking theconcentration wa
s reduced by 85%. However, a
spectrophotometric method
specific for heme iron
showed thatit wa
s still intact, even after heating to 80
s/entitie
s/deg.gif">C. Themea
surement of the total iron in the cooked
steak andthe HPLC extract
s by inductively coupled pla
sma opticalemi
ssion
spectro
scopy (ICP-OES) indicated that theextraction method for the HPLC analy
si
s wa
s no longerapplicable and that lo
ss of the heme group from theprotein rendered it incompatible with the
size exclu
sion
separation. The detection limit (concentration equivalentto 3 time
s the ba
seline for a blank injection) of the HPLC-ICPMS method wa
s 2.4 ng a
s iron. The re
sult
s demon
strate that a combination of analytical method
s can beu
sed to provide valuable information about dietary level
sof nutritionally important metal-containing compound
s a
swell a
s the efficiency of e
stabli
shed extraction method
sfor raw and cooked meat
sample
s.