Determination of iodine and bromine compounds in foodstuffs by CE-inductively coupled plasma MS.
A CE-inductively coupled plasma mass spectrometric (CE-ICP-MS) method for iodine and bromine speciation analysis is described. Samples containing ionic iodine (I(-) and IO(3)(-)) and bromine (Br(-) and BrO(3)(-)) species are subjected to electrophoretic separation before injection into the microconcentric nebulizer (CEI-100). The separation has been achieved in a 50 cm length x 75 microm id fused-silica capillary. The electrophoretic buffer used is 10 mmol/L Tris (pH 8.0), while the applied voltage is set at -8 kV. Detection limits are 1 and 20-50 ng/mL for various I and Br compounds, respectively, based on peak height. The RSD of the peak areas for seven injections of 0.1 microg/mL I(-), IO(3)(-) and 1 microg/mL Br(-), BrO(3)(-) mixture is in the range of 3-5%. This method has been applied to determine various iodine and bromine species in NIST SRM 1573a Tomato Leaves reference material and a salt and seaweed samples obtained locally. A microwave-assisted extraction method is used for the extraction of these compounds. Over 87% of the total iodine and 83% of the total bromine are extracted using a 10% m/v tetramethylammonium hydroxide (TMAH) solution in a focused microwave field within a period of 10 min. The spike recoveries are in the range of 94-105% for all the determinations. The major species of iodine and bromine in tomato leaves, salt, and seaweed are Br(-), IO(3)(-), I(-), and Br(-), respectively.
Chen
Jing-Huan
JH
Department of Chemistry, National Sun Yat-sen University, Kaohsiung, Taiwan.
Wang
Kai-en
KE
Jiang
Shiuh-Jen
SJ
D017605:Bromine Compounds / Q000032:analysis*; D002021:Buffers; D019075:Electrophoresis, Capillary / Q000379:methods; D005504:Food Analysis / Q000379:methods* / Q000592:standards; D017613:Iodine Compounds / Q000032:analysis*; D018551:Solanum lycopersicum; D018515:Plant Leaves / Q000737:chemistry; D012492:Salts; D012624:Seaweed / Q000737:chemistry; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods* / Q000592:standards
D017605:Bromine Compounds; D002021:Buffers; D017613:Iodine Compounds; D012492:Salts