Determination of 30 elements in colorectal biopsies by sector field inductively coupled plasma mass spectrometry: method development and preliminary baseline levels Beatrice Bocca 1 , Antonella Lamazza 2 , Anna Pino 1 , Ercole De Masi 3 , Maura Iacomino 3 , Daniela Mattei 1 , Siavash Rahimi 3 , Enrico Fiori 2 , Alberto Schillaci 2 , Alessandro Alimonti 1 * and Giovanni Forte 1 1 Istituto Superiore di Sanita `, Department of Environment and Primary Prevention, Viale Regina Elena 299, 00161 Rome, Italy 2 Hospital ‘Umberto I’, Viale del Policlinico 155, 00161 Rome, Italy 3 Hospital ‘San Carlo’, IDI IRCCS, Via Aurelia 275, 00165 Rome, Italy Received 22 February 2007; Revised 28 March 2007; Accepted 28 March 2007 An analytical procedure applicable to restricted sample sizes was developed and applied to the analysis of 30 chemical elements in colorectal biopsies of healthy patients. Acidic microwave digestion processed £10 mg of tissue at 80-C in 15-mL polystyrene liners. The digests were diluted to a volume of 2 mL with high-purity water and directly analyzed by sector field inductively coupled plasma mass spectrometry without further specimen handling. A careful selection of isotopes and instrumental resolution permitted the quantification in a single analytical sequence both of the elements present at parts per trillion and of those at parts per million. The accuracy calculated on BCR 184 ranged from 93.3–110%, the recoveries of the biopsy material was in the range 95.2–105%, the precision was <10%, and the blank levels were much below those expected in biopsy samples. The metal concentrations (on a dry-weight basis) in colorectal normal tissue showed a large range of variation: Ag, Au, Be, Bi, Co, Li, Sb, Tl, V, W and Zr were below 50 ng g S1 ; As, Ba, Cd, Cr, Cs, Hg, Mo, Ni, Pb, Se and Sn were distributed from 100 to 500 ng g S1 ; Al, Cu, Fe, Mn, Sr and Zn were from a few mgg S1 to 100 mgg S1 ; and Ca and Mg were at a level of 1000 mgg S1 . These data represent the first attempt to achieve an elemental profile in the colorectal mucosa of healthy patients as baseline level measurements for studies focused on the imbalance of chemical elements in diseased mucosa. Copyright # 2007 John Wiley & Sons, Ltd. Assessment of the elemental profile in human tissues is essential to extending knowledge on the healthy and the diseased states. From this point of view, colon-rectal mucosa has been rarely and not fully characterized. In general, studies on elemental concentration involved only one (e.g., Se or Mg) 1,2 or a few analytes such as Cu, Cd, Cr, Se, Ni and Zn. 3–9 Information about other elements such as Al, Ba, Ca, Co, Hg, Mg, Mn, Pb, and Fe is rather sparse. 10–12 An imbalance in the normal homeostasis of essential elements and tissue accumulation of potential toxic metals might, however, be associated with the risk of developing diseases such as colorectal cancer. 13–17 This paucity of information on elemental profiles can be traced back to the difficulties inherent in the multi-elemental analysis of biological tissues. First, the amount of the biological sample is often limited – for example, only a few milligrams of sample are available from human tissue biopsies. Secondly, the analytes of interest often occur at trace (ng g 1 ) or ultratrace (from pg g 1 to fg g 1 ) concentration level. In addition, tissue matrix contains high amounts of interferents which can affect the final analytical results. The biological matrix can be mineralized by use of conventional hot plates and furnaces but these procedures take time to complete the digestion and cause possible contamination and loss of analytes. Microwave (MW) digestion in PTFE closed vessels has advantages over conventional methods because it reduces external contami- nation and achieves total recovery of elements. 18 Never- theless, treatment by a high-pressure MW system is not ideal when samples are of small sizes, such as human biopsies, because of the large volume of the vessels (100 mL). Further, the method does not facilitate routine sample preparation RAPID COMMUNICATIONS IN MASS SPECTROMETRY Rapid Commun. Mass Spectrom. 2007; 21: 1776–1782 Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/rcm.3016 *Correspondence to: A. Alimonti, Istituto Superiore di Sanita `, Department of Environment and Primary Prevention, Viale Regina Elena 299, 00161 Rome, Italy. E-mail: alessandro.alimonti@iss.it Contract/grant sponsor: LILT, Lega Italiana per la Lotta contro i Tumori (Italian League against Cancer); contract/grant number: ISS/N3A (2006-08). Copyright # 2007 John Wiley & Sons, Ltd.