TITLE:
Copper and Mercury in Food, Biological and Pharmaceutical Samples: Spectrophotometric Estimation as Cu(DDTC)2
AUTHORS:
Mohammad Nasir Uddin, Nur Mostaq Shah, Mohammad Amzad Hossain, Md. Muzahidul Islam
KEYWORDS:
Copper, Mercury, Diethyldithiocarbamate, Spectrophotometric Method, Food, Biological, Pharmaceutical Samples
JOURNAL NAME:
American Journal of Analytical Chemistry,
Vol.5 No.13,
September
19,
2014
ABSTRACT: An alternative
spectrophotometric method was optimized and validated for the estimation of mercury using diethyldithiocarbamate (DDTC), a common reagent, widely used for the
preconcentration and isolation of metal ions in complex matrices followed by
their estimation by varied techniques. Diethyldithiocarbamate forms yellow
Cu(DDTC)2 with copper and white Hg(DDTC)2 with mercury
(having d10 system) which are extracted in CCl4. The
UV-visible spectrum of Cu(DDTC)2 is very stable at pH 5.0 and has a
maximum absorption (λmax)
at 435 nm. Hg(DDTC)2 is more stable than Cu(DDTC)2.
Estimation of mercury is based on a quantitative displacement of Cu(II) of
Cu(DDTC)2 with the addition of mercury followed by the measurement
of reduced absorbance. Primarily, method was optimized and validated for the
estimation of copper. Therefore, simultaneous determination of Cu(II) and
Hg(II) in mixture is proposed fractionating the extract. The molar specific
coefficient (ε) for the mercury was 1.4
× 104 mol﹣1·L·cm﹣1 and for copper was 3.16 × 105 mol﹣1·L·cm﹣1 at 435 nm. The detection limits of Cu2+ and Hg2+ were 0.023 μg·mL﹣1 and 0.029 μg·mL﹣1,
respectively. The calibration curve shows good linearity of 0.02 - 12.0 and
0.02 - 15.0 μg·mL﹣1 for the Cu2+ and Hg2+ determination, respectively. Proposed technique was applied to food, biological
and pharmaceutical samples for the determination of Cu(II) and Hg(II).