Homemade Capillary Electrophoresis Coupled to a Mass Spectrometer

A system was developed in our laboratory to couple capillary electrophoresis with mass spectrometry. the capillary electrophoresis system was equipped with a high voltage supply, and a microcontroller with assembly language programming was developed for the computational control of the system. the MS system was a commercial Thermo Finningan LCQ ion trap mass spectrometer. the robustness of the coupled system was evaluated using standard protein samples (lysozyme, aprotinin, and bovine albumin) and tryptic digests of lysozyme. the system showed positive results in terms of robustness, allowing for the separation of digested proteins and the identification of 33% of the total amino acids in a protein (6 of the 18 expected peptides). the limit of detection was in the order of 1 picomole (signal-to-noise ratio), which was considered satisfactory for this system. the system shows high versatility in tandem coupling and combinations with other analytical procedures.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Universidade Federal de São Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Exatas & Terra Diadema, São Paulo, BrazilUniv São Paulo, Inst Quim Sao Carlos, São Paulo, BrazilUniversidade Federal de São Paulo, Inst Ciencias Ambientais Quim & Farmaceut, Dept Ciencias Exatas & Terra Diadema, São Paulo, BrazilWeb of Scienc

Bioanalytical studies of porphyric disorders using HPLC with fluorescence detection

We describe here the development, validation, quantification and application of a method for determination of heme porphyrin precursors in the urine of porphyric patients. The isomers coproporphyrinogen I and III (COPRO I and III), uroporphyrinogen I (URO I), heptacarboxylporphyrinogen I (HEPTA I), pentacarboxylporphyrinogen (PENTA I), and hexacarboxylporphyrinogen I (HEXA I) were analyzed. These six urinary heme precursors were determined in urine samples collected from 24 patients by high-performance liquid chromatography (HPLC) equipped with a fluorescence detector. The inter- and intra-day precision (coefficient of variation < 5%) and accuracy (95-99%) were evaluated. The limits of detection and of quantification of the porphyrins, expressed in nmol L-1, were as follows: URO I, 0.62 and 2.05; HEPTA I, 0.59 and 1.96; HEXA I, 0.54 and 1.81; PENTA I, 0.52 and 1.73; COPRO I, 2.03 and 6.77; and COPRO III, 0.43 and 1.44. The method described here satisfactorily results in an acceptable cost-benefit ratio, precision and speed for determining the concentrations of heme precursors in the urine of latent or symptomatic acute intermittent porphyria individuals or porphyria cutanea tarda carriers. Since it was analytically validated, this method may be used for accurate and reliable diagnostic reports to follow-up the onset of acute crisis in porphyria carriers to adopt preventive pharmacological treatment.Neste artigo, desenvolvemos, validamos e aplicamos um método para separação e quantificação de porfirinas precursoras do grupo heme na urina de portadores de porfirias. Os isômeros coproporfirinogenio I e III (COPRO I e III), uroporfirinogenio I (URO I), heptacarboxilporfirinogenio I (HEPTA I), pentacarboxilporfirinogenio I (PENTA I) e hexacarboxilporfirinogenio (HEXA I) foram determinados em amostras coletadas de 24 pacientes de porfiria aguda intermitente e de porfiria cutânea tarda. Utilizou-se cromatografia líquida de alta eficiência (HPLC) e detector de fluorescência. As concentrações de porfirinas foram determinadas com precisão inter e intra-dias (< 5%) e exatidão dentro da faixa 95-99%. Os limites de detecção e quantificação das porfirinas, expressos em nmol L-1, foram os seguintes: URO I, 0,62 e 2,05; HEPTA I, 0,59 e 1,96; HEXA I, 0,54 e 1,81; PENTA I, 0,52 e 1,73; COPRO I, 2,03 e 6,77; e COPRO III, 0,43 e 1,44. O método descrito aqui obedece a parâmetros analíticos satisfatórios, com excelente relação custo-benefício, e foi aplicado a amostras de urina de portadores assintomáticos e pacientes de porfirias. Este método foi validado analiticamente e mostrou potencial para diagnóstico de portadores de diferentes tipos de porfirias, imediatamente antes ou durante crises, e até mesmo para monitorar um tratamento farmacológico.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)INCT Redoxoma Redox Processes in BiomedicineFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Universidade Federal de São Paulo (UNIFESP) Instituto de Ciências Ambientais, Químicas e Farmacêuticas Departamento de Ciências Exatas e da TerraUniversidade de São Paulo Instituto de Química Departamento de Química FundamentalUNIFESP, Instituto de Ciências Ambientais, Químicas e Farmacêuticas Depto. de Ciências Exatas e da Terra2006/60245-3 e 2006/56530-4SciEL

Is chemical exposure present in informal work associated with Sars-CoV-2 infection?

OBJECTIVE: To compare the incidence of Covid-19 symptoms between informal home-based workers and a control group and to assess the association of these cases with blood elements concentrations and other relevant risk factors for Sars-Cov-2 infection. METHODS: Welders chemically exposed to potentially toxic elements (PTEs) (n = 26) and control participants (n = 25) answered questionnaires on adherence to social distancing and signs and symptoms of the disease for five months during the Covid-19 pandemic. After follow-up, Covid-19 serology tests were performed on a subsample of 12 chemically exposed workers and 20 control participants. Before the pandemic, PTE concentrations in blood (As, Mn, Ni, Cd, Hg, Sb, Sn, Cu, Zn, and Pb) were measured by ICP-MS. RESULTS: The chemically exposed group had higher lead and cadmium levels in blood (p &lt; 0.01). The control group presented lower adherence to social distancing (p = 0.016). Although not significant, welders had a 74% greater chance of having at least one Covid-19 symptom compared with control participants, but their adherence to social distancing decreased this chance by 20%. The use of taxis for transportation was a risk factor significantly associated with Covid-19 symptoms. CONCLUSION: The lower adherence to social distancing among the control group greatly influences the development of Covid-19. The literature lacks data linking exposure to PTEs and Sars-Cov-2 infection and/or severity. In this study, despite chemical exposure, working from home may have protected welders against Covid-19, considering that they maintained greater social distancing than control participants