## 1 Introduction  
Nuclear magnetic resonance (NMR) has been widely recognized as a powerful and effective method for chemical structure identification and analysis since its discovery in the early 1940s [1, 2, 3]. The continuous advancements in superconducting pulse Fourier transform technology have significantly improved the sensitivity of NMR quantitative analysis and greatly reduced analysis time, making it widely adopted by the 1970s [4]. Quantitative nuclear magnetic resonance (qNMR) has garnered significant attention and applications in international metrological comparisons since the early 21 st century [5, 6, 7, 8]. Conventional techniques like high-performance liquid chromatography and UV-visible spectrophotometry are widely employed for quantification. Nonetheless, NMR has gained prominence for its non-invasive properties, rapid analysis, and high throughput, earning its place in numerous national pharmacopoias.  
In detail, the broad acceptance of NMR for quantitative analysis stems from a range of distinct advantages, including the following: (i) The capability to analyze molecular structures: NMR spectroscopy provides diverse information about molecular structures, allowing for precise identification and analysis of compounds. (ii) Direct proportionality of signal area to the number of nuclei: When calculating ratios, NMR eliminates the need for intensity calibrations because the signal area directly correlates with the number of nuclei present. (iii) Faster analysis: NMR offers relatively quick measurement times, improving the efficiency of analytical workflows. (iv) Preservation of samples: As a non-destructive method, NMR maintains the sample's integrity, allowing for additional analyses or future use. (v) No requirement for prior isolation of the analyte in a mixture: NMR can analyze components within a mixture without necessitating prior isolation of the analyte. (vi) Simultaneous determination of multiple analytes: NMR allows for the simultaneous determination of multiple analytes within a mixture, streamlining the analytical process. (vii) Easy sample preparation and handling: Sample preparation for NMR is generally straightforward, facilitating ease of use in various applications [9]. These advantages contribute to the widespread adoption of NMR in quantitative measurements across diverse fields.  
qNMR is a highly accurate absolute quantification method widely used in various fields to assess the purity of compounds. While \({}^{1}\)H qNMR is common, signal overlap in complex compounds can hinder accuracy. Therefore, \({}^{31}\)P-qNMR was investigated as an alternative because of its straightforward approach and greater sensitivity compared to other NMR-active nuclei. This article introduces the unique advantages of \({}^{31}\)P in nuclear magnetic resonance as well as recent research advancements in \({}^{31}\)P qNMR methods. It also discusses recent progress in the application of \({}^{31}\)P qNMR across various fields.  
This paper is organized into four sections, each describing different aspects of the outline and application of phosphorus-containing compounds in quantitative \({}^{31}\)P NMR spectroscopy. The first section covers the fundamental principles of NMR spectroscopy, including the structure and components of NMR spectrometers. The second section provides a brief description of the specific advantages of qNMR and the unique attributes of \({}^{31}\)P nuclei. The third section explores various applications of \({}^{31}\)P qNMR across fields such as food analysis, pharmaceuticals, and biology. The final section concludes by addressing the future prospects of \({}^{31}\)P qNMR, highlighting its potential for broader applications with ongoing advancements in NMR technology and sensitivity enhancements.