Determination of iodine and bromine compounds in foodstuffs by CE-inductively coupled plasma MS

Multielemental speciation analysis by advanced hyphenated technique - HPLC/ICP-MS: A review

Speciation analysis has become an invaluable tool in human health risk assessment, environmental monitoring or food quality control. Another step is to develop reliable multielemental speciation methodologies, to reduce costs, waste and time needed for the analysis. Separation and detection of species of several elements in a single analytical run can be accomplished by high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Our review assembles articles concerning multielemental speciation determination of: As, Se, Cr, Sb, I, Br, Pb, Hg, V, Mo, Te, Tl, Cd and W in environmental, biological, food and clinical samples analyzed with HPLC/ICP-MS. It addresses the procedures in terms of following issues: sample collection and pretreatment, selection of optimal conditions for elements species separation by HPLC and determination using ICP-MS as well as metrological approach. The presented work is the first review article concerning multielemental speciation analysis by advanced hyphenated technique HPLC/ICP-MS.

Analysis of potassium iodate reduction in tissue homogenates using high performance liquid chromatography-inductively coupled plasma-mass spectrometry

Potassium iodate (KIO3) and potassium iodide (KI) are the major salt iodization agents used worldwide. Unlike iodide (I(-)), iodate (IO3(-)) should be reduced to I(-) before it can be effectively used by the thyroid. In this study, we developed a new method for analyzing IO3(-) and I(-) in tissue homogenates using high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). We further applied the method to demonstrate the KIO3 reduction process by tissues in vitro. The effects of KIO3 on the total antioxidative activity (TAA) and reduced nicotinamide adenine dinucleotide phosphate (NADPH) were also investigated here. Finally, we found that IO3(-) can be reduced to I(-) by tissue homogenates and IO3(-) irreversibly decreases the antioxidant capability of tissues. Our studies suggest that KIO3 might have a big effect on the redox balance of tissue and would further result in oxidative stress of organisms.

Analytical methods for the determination of halogens in bioanalytical sciences: a review

Fluorine, chlorine, bromine, and iodine have been studied in biological samples and other related matrices owing to the need to understand the biochemical effects in living organisms. In this review, the works published in last 20 years are covered, and the main topics related to sample preparation methods and analytical techniques commonly used for fluorine, chlorine, bromine, and iodine determination in biological samples, food, drugs, and plants used as food or with medical applications are discussed. The commonest sample preparation methods, as extraction and decomposition using combustion and pyrohydrolysis, are reviewed, as well as spectrometric and electroanalytical techniques, spectrophotometry, total reflection X-ray fluorescence, neutron activation analysis, and separation systems using chromatography and electrophoresis. On this aspect, the main analytical challenges and drawbacks are highlighted. A discussion related to the availability of certified reference materials for evaluation of accuracy is also included, as well as a discussion of the official methods used as references for the determination of halogens in the samples covered in this review.

Thirty years of capillary electrophoresis in food analysis laboratories: potential applications

CE has generated considerable interest in the research community since instruments were introduced by different trading companies in the 1990s. Nowadays, CE is popular due to its simplicity, speed, highly efficient separations and minimal solvent and reagent consumption; it can also be included as a useful technique in the nanotechnology field and it covers a wide range of specific applications in different fields (chemical, pharmaceutical, genetic, clinical, food and environmental). CE has been very well evaluated in research laboratories for several years, and different new approaches to improve sensitivity (one of the main drawbacks of CE) and robustness have been proposed. However, this technique is still not well accepted in routine laboratories for food analysis. Researching in data bases, it is easy to find several electrophoretic methods to determine different groups of analytes and sometimes they are compared in terms of sensitivity, selectivity, precision and applicability with other separation techniques. Although these papers frequently prove the potential of this methodology in spiked samples, it is not common to find a discussion of the well-known complexity of the matrices to extract analytes from the sample and/or to study the interferences in the target analytes. Summarizing, the majority of CE scientific papers focus primarily on the effects upon the separation of the analytes while ignoring their behavior if these analytes are presented in real samples.

Recent advances in CE-MS: Synergy of wet chemistry and instrumentation innovations

CE with MS detection is a hyphenated technique which greatly improves the ability of CE to deal with real samples, especially with those coming from biology and medicine, where the target analytes are present as trace amounts in very complex matrices. CE-MS is now almost a routine technique performed on commercially available instruments. It faces currently a tremendous development of the technique itself as well as of its wide application area. Great interest in CE-MS is reflected in the scientific literature by many original research articles and also by numerous reviews. The review presented here has a general scope and belongs to a series of regularly published reviews on the topic. It covers the literature from the last 2 years, since January 2008 till June 2010. It brings a critical selection of related literature sorted into groups reflecting the main topics of actual scientific interest: (i) innovations in CE-ESI-MS, (ii) use of alternative interfaces, and (iii) ways to enhance sensitivity. Special attention is paid to novel electrolyte systems amenable to CE-MS including nonvolatile BGEs, to advanced CE separation principles such as MEKC, MEEKC, chiral CE, and to the use of preconcentration techniques.

Recent advances in the application of capillary electromigration methods for food analysis and Foodomics

The use of capillary electromigration methods to analyze foods and food components is reviewed in this work. Papers that were published during the period April 2007 to March 2009 are included following the previous review by García-Cañas and Cifuentes (Electrophoresis, 2008, 29, 294-309). These works include the analysis of amino acids, biogenic amines, peptides, proteins, DNAs, carbohydrates, phenols, polyphenols, pigments, toxins, pesticides, vitamins, additives, small organic and inorganic ions and other compounds found in foods and beverages, as well as those applications of CE for monitoring food interactions and food processing. The use of microchips, CE-MS, chiral-CE as well as other foreseen trends in food analysis are also discussed including their possibilities in the very new field of Foodomics.

Recent food safety and food quality applications of CE-MS

The first on-line coupling of CE with MS detection more than 20 years ago provided a very powerful technique with a wide variety of applications, among which food analysis is of special interest, especially that dealing with food safety and food quality applications, the major topics of public interest nowadays. With this review article, we would like to show the most recent applications of CE-MS in both fields by recompiling and commenting articles published between January 2004 and October 2008. Although both applications are difficult to separate from each other, we have included in this work two main sections dealing with each specific field. Future trends will also be discussed.

Sensitive determination of bromine and iodine in aqueous and biological samples by electrothermal vaporization inductively coupled plasma mass spectrometry using tetramethylammonium hydroxide as a chemical modifier

A procedure for the simultaneous determination of bromine and iodine by inductively coupled plasma (ICP) mass spectrometry was investigated. In order to prevent the decrease in the ionization efficiencies of bromine and iodine atoms caused by the introduction of water mist, electrothermal vaporization was used for sample introduction into the ICP mass spectrometer. To prevent loss of analytes during the drying process, a small amount of tetramethylammonium hydroxide solution was placed as a chemical modifier into the tungsten boat furnace. After evaporation of the solvent, the analytes instantly vaporized and were then introduced into the ICP ion source to detect the (79)Br(+), (81)Br(+), and (127)I(+) ions. By using this system, detection limits of 0.77 pg and 0.086 pg were achieved for bromine and iodine, respectively. These values correspond to 8.1 pg mL(-1) and 0.91 pg mL(-1) of the aqueous bromide and iodide ion concentrations, respectively, for a sampling volume of 95 microL. The relative standard deviations for eight replicate measurements were 2.2% and 2.8% for 20 pg of bromine and 2 pg of iodine, respectively. Approximately 25 batches were vaporizable per hour. The method was successfully applied to the analysis of various certified reference materials and practical situations as biological and aqueous samples. There is further potential for the simultaneous determination of fluorine and chlorine.