食品检测用SPEX冷冻研磨机来低温研磨食物样品再以石墨炉

Abstract A simple method combining slurry samp领
after cryogenic grinding and the use of a permanent modification
of the integrated platform inside the transversely
heated graphite atomizer (THGA) was proposed for the
determination of Cd and Pb in foods. Potentialities of the
cryogenic grinding were evaluated for grinding different
materials of difficult homogenization such as high fat and
high fiber tissues. Animal and vegetal samples were cut
into small pieces and ground in liquid nitrogen for 2 min.
Slurries were prepared directly in the autosampler cup after
cryogenic grinding by transferring an exact amount of
homogeneous powdered material (520 mg) to the cup,
followed by 1.00 mL of 0.2% (v/v) HNO3 containing 0.04%
(v/v) Triton X-100 and sonication for 30 s, before transferring
into the platform previously coated with 250 g W
and 200 g Rh. Use of a tungsten carbide-rhodium permanent
modifier combined with NH4H2PO4 conventional
modifier improves tube lifetime and increases the pyrolysis
temperature for Cd. Homogeneity tests, carried out by
comparing the between- and within-batch precision for
each kind of sample, showed no significant differences at
the 95% confidence level, indicating good homogeneity
for 520 mg masses. Detection limits were 3.3 ng g1 Cd
and 75 ng g1 Pb for 1% m/v slurries. Results for determination
of Cd and Pb in foods slurries were in agreement
with those obtained with digested samples, since no statistical
differences were found by the paired t-test at the
95% level. SPEX6770 全自动冷冻研磨机 SPEX6870 全自动冷冻研磨机 SPEX6970EFM 冷冻研磨机