Sensitivity improvement of solution cathode glow discharge-optical emission spectrometry by external magnetic field for optical determination of elements

•Improvement of the sensitivity of SCGD using a magnetic field was investigated.•The proposed method does not require changes to the original operating procedures.•The effect of magnetic field was explained by calculating the electron temperature.•Detection limits of SCGD with a 0.65 T magnetic field were greatly improved. A method has been developed to improve elemental determination by solution cathode glow discharge (SCGD) optical emission spectrometry. The introduction of a 0.65 T external magnetic field to the plasma discharge cell considerably enhanced the metal signal. Compared with the field-free case under the same voltage condition (400 V), the net intensities of the atomic emission lines of Cd, Cu, Pb, and Zn are enhanced by a factor of 2.9, 2.3, 2.1, and 3.2 in the presence of the external magnetic field, respectively. Moreover, the external magnetic field improved signal stability and extended the discharge voltage range from 300–420 V to 340–510 V. When the voltage was 490 V with a 0.65 T magnetic field, the emission intensity can be further enhanced by a factor of 4.2, 3.7, 3.1, and 5.0 for Cd, Cu, Pb, and Zn, respectively. The established limits of detections (LODs) are several times better as those obtained without a magnetic field at 400 V. The accuracy of the proposed method was demonstrated by the determination of elements in the standard water samples.