Sample Preparation Using TMAH and Nitric Acid for Multielement Determination in Crustacean Samples by MIP OES

This study proposes a simple sample preparation procedure using tetramethylammonium hydroxide (TMAH) and nitric acid (HNO3) to determine Cr, Cu, Fe, K, Mg, Mn, and Zn concentrations in shrimp (Macrobrachium amazonicum) and crab (Ucides cordatus) samples from the Amazon region by microwave-induced plasma optical emission spectrometry (MIP OES). The sample solubilization was carried out employing TMAH and HNO3 using an ultrasound bath and a thermostatic water bath. The accuracy of the proposed procedure was performed using microwave-assisted digestion as comparative method. Certified fish protein reference material (DORM-4) and also addition recovery experiments were used to assess the accuracy of the proposed procedure and recoveries obtained were adequate, ranging from 91 to 106%. In this study, the use of TMAH and HNO3 simplified sample preparation, maintaining the identity of analytes and ensuring efficiency in determinations.

本研究提出了一种以四甲基氢氧化铵（tetramethylammonium hydroxide, TMAH）和硝酸（nitric acid, HNO₃）为试剂的简易样品前处理流程，用于通过微波诱导等离子体光发射光谱法（microwave-induced plasma optical emission spectrometry, MIP OES）测定采自亚马逊区域的虾类（亚马逊沼虾 *Macrobrachium amazonicum*）与蟹类（痕掌沙蟹 *Ucides cordatus*）样品中铬（Cr）、铜（Cu）、铁（Fe）、钾（K）、镁（Mg）、锰（Mn）及锌（Zn）的浓度。样品消解过程采用四甲基氢氧化铵与硝酸作为试剂，并结合超声浴与恒温水浴完成。本研究以微波辅助消解法作为对照方法，对所提流程的准确度进行验证；同时采用认证鱼蛋白标准物质（DORM-4）与加标回收实验评估该方法的准确度，所得回收率介于91%至106%之间，符合实验要求。本研究证实，采用该四甲基氢氧化铵与硝酸体系的样品前处理流程可有效简化操作，同时保留分析物的固有特性并保障测定的高效性。