Possibility of direct rapid determination of inorganic contaminant elements in paints by LA-ICP-MS method

Abstract

In this work content of inorganic major and trace elements were directly determined in produced in China, Russia, and Germany household use purpose oil, асгуI, and ochre paint samples using laser ablation-inductively coupled plasma-mass spectroscopy (LA_ICP_MS) technique. A sample preparation was simple and rapid: an oil and acryl paint droplets were dried on glass substrate for several hours on a hot plate at 60° C and few mg ochre paint powder samples were solidified with pure paraffin wax on the glass substrate. Dried oil and acryl paint droplets were ablated locally, drilling the hole way, while ochre paint powders were ablated using surface rastering method. Contents of inorganic elements were calculated using the NIST 610 glassy standard sample as the reference. Parallel determination results of lead and chromium in oil paint samples by atomic absorption technique correlates with that of by LA_ICP_MS acceptably (correlation coefficient for lead is 0.85 and for chromium is 0.95). Because of sample organic - reference inorganic matrix difference, the measured by the LA_ICP_MS content of each element must be adjusted being multiplied in some quantity, value of which are different for each element. For lead and chromium value of the quantity found correspondingly as 6.4 and 9.3. The average relative standard deviation (RSD) of measured content of the mostly high content elements Ca, Al, Mn, Pb, Sr, S, Mg, Fe, Sb, Na, Co, Si, Zn, Cu, P, Y, K, CI, Ce, and La is less than 10%, the RSD for elements Ti, Cr, Sn, Ba, Zr, Rb lies between 10 and 20%, and the RSD for trace elements Gd, Nb, Sc, V, U. Pr, Ni, Ga, Eu, As, Th B, Mo, Cd, Li lies in interval from 20 to 50 %. High level of concentration 309 - 24300 ppm for lead, 950- 3134 ppm for chromium are detected by LA-ICP-MS method in samples of red, yellow and green color oil paints produced in China and bestselling in Mongolia certain brand products. Up to 1900 ppm alarming high content of arsenic is tovnd in the Chinese origin yellowish red, brown red color ochre paints. As shows our measurements, the LA-ICP-MS method is possible to use as alternative rapid semi-quantitive detection method with acceptable accuracy and precision for basic inorganic additives in oil, acryl and ochre paints using glassy standard sample.