Humans have been exposed to thousands of chemicals every day and over the whole lifetime. We are intentionally exposed to some chemicals such as food, cosmetics, and medicines. But we are also unintentionally exposed to the other chemical like contaminants in drinking water, detergents, and air pollutants. Additionally, thousands of new chemicals are produced every year rapidly since the industrial revolution. Even the most advanced chemical analysis instrumentation is not enough for determining the extent of the chemicals we are exposed to. The objective of this research is to characterise the limitations of current analytical methods to understand the human exposome particularly in regards to limitations of high-resolution mass spectrometry (HRMS). Specifically, a set reference standards is developed to benchmark different non-targeted HRMS methods and characterise the chemical space of these methods. Molecular weight and partition coefficient log P are selected as two physico-chemical descriptors for visualising chemical space of US EPA chemical inventory of 700k chemical species. Visualised space is divided by each 200 molecular weight and each 2 log P value. And then representative chemical standard with at least one spectral information from public library for each grid is selected for positive and negative polarity. These benchmark standards will be used for characterising typical preparation methods in regards to their chemical space. This research will visualise the chemical space dimensions of the exposome that can be measured using high-resolution mass spectrometry techniques. Additionally this will help us understand the limited coverage of various methods and what needs improvement to better characterise the exposome.