Flame atomic absorption spectrometry (FAAS) and inductively coupled plasma optical emission spectrometry (ICP OES) are widely used in academic institutions and laboratories for quality control to analyze inorganic elements in samples. However, these techniques have been observed to underperform in sample nebulization processes. Most of the samples processed through nebulization system are discarded, producing large volumes of waste. This study reports the treatment and reuse of the waste produced from ICP OES technique in a laboratory of analytical research at the Universidade Federal do Ceará, Brazil. The treatment of the waste was performed by the precipitation of elements using (NH4)2CO3. Subsequently, the supernatant solution can be discarded in accordance with CONAMA 430/2011. The precipitate produced from the treatment of residues can be reused as a potential sample in undergraduate qualitative analytical chemistry lab classes, providing students the opportunity to test a real sample.

Simple experiments are proposed for measuring molecular absorption of chromate and dichromate ions using an atomic absorption spectrometer. The experiments can help undergraduate students in instrumental analysis courses understand important aspects involving conceptual and instrumental similarities and differences between frequently used analytical techniques. Hollow cathode lamps were selected with wavelengths in the region of molecular absorption of chromate and dichromate. Calibration curves were obtained and the linear dynamic range was evaluated. Results were compared with those obtained in a molecular absorption spectrometer. The molar absorptivities obtained were also compared.

Neste trabalho investigou-se um procedimento de preparo de amostras, com rápido aquecimento da suspensão da amostra em meio ácido usando radiação infravermelho emitida por lâmpadas de tungstênio. As vantagens do procedimento proposto são a simplicidade e o baixo custo. A solução diluída do ácido é aquecida em tempo inferior a 60 s e o tempo total do preparo da amostra é menor que 5 min. O procedimento proposto pode ser facilmente implementado para a análise de elementos presentes em baixas concentrações. Avaliações preliminares foram feitas determinando-se os teores de Cu, Fe, Mn e Zn em material de referência certificado de fígado bovino e folha de maçã. Todos os resultados foram avaliados com nível de confiança de 95%. Os teores determinados de Cu e Mn foram comparados em amostra de fígado bovino sem tratamento prévio ou após liofilização. Para essa amostra, os resultados foram validados empregando-se procedimento de decomposição assistida por microondas em frasco fechado.

A procedure for sample preparation was investigated in this work using infra-red radiation generated by tungsten lamps for fast heating of an acidic sample suspension contained in a glass flask. The main advantages of the developed procedure are its simplicity and low-cost. Additionally the dilute acid solution is heated in less than 60 s and the total sample preparation is performed in less than 5 min. The proposed procedure is suitable for trace analysis and it can be easily implemented. The preliminary investigations focus on the determination of Cu, Fe, Mn, and Zn in bovine liver and apple leaves as standard reference materials. All results are in agreement at a 95% confidence level. Copper and Mn were also determined in a sample of bovine liver without any sample pretreatment or after a freeze-drying step for comparison. For this sample, the results were validated using a conventional microwave-assisted closed vessel procedure.