Abstract: National and industry standard methods such as X-ray fluorescence spectrometry, flame atomic absorption spectrometry, inductively coupled plasma emission spectrometry, and fire assay gravimetry are commonly used to detect the purity of gold and silver raw materials and products. However, these methods only cover around 20 conventional major and impurity elements, while there are no standard methods or literature reports available for gaseous or certain non-conventional elements. This study employed a combination of detection techniques, including fire assay gravimetry, glow discharge mass spectrometry, inductively coupled plasma emission spectrometry, inductively coupled plasma mass spectrometry, inert gas fusion-infrared absorption thermal conductivity method, combustion infrared method, and thermogravimetric analysis to detect non-conventional and gaseous elements that affect the purity of gold and silver. Results show that different national and industry standard methods yield varying purity results for the same gold and silver samples of conventional purity. Fire assay gravimetry is preferred for determining the gold content. For gold materials and products with gold content greater than 99.95 %, the main content should first be determined by fire assay gravimetry; if it meets the required standard, conventional methods for detecting impurities can be used to calculate the final purity by subtraction. During the subtraction process, possible introduction of non-conventional elements during raw material sourcing and production must be fully considered.