[Optimizing experimental conditions of graphite furnace atomic absorption spectrometer using orthogonal design for determination of cobalt in urine].

Objective: To select and optimize the conditions of urine cobalt determination by graphite furnace atomic absorption spectroscopy and establish a method for urine cobalt determination. Methods: In April 2020, the matrix modifier and spectrum wavelength were selected by mathematical statistics method, the heating procedure of graphite furnace was optimized, the variance of orthogonal test results was analyzed, and the working curve was quantified by external standard method. Results: The results showed that the diammonium hydrogen phosphate was a matrix modifier with a wavelength of 240.7 nm, and the optimized graphite furnace heating procedure showed a good linear relationship at 5-80 μg/L. The correlation coefficient was 0.9991. The detection limit was 0.9 μg/L, the lowest detection concentration was 1.8 μg/L. The recovery was 94.0%-101.4%, and the precision was 2.6%-5.8%. Conclusion: The orthogonal design method can efficiently and scientifically optimize the optimal combination of the various factor levels of graphite furnace atomic absorption spectrometry. The determination method established based on this has high precision and good accuracy, and can be applied to the determination of cobalt in urine.