Ruoning Guo, Anna M Röhnelt, Philipp R Martin, Stefan B Haderlein
{"title":"有机膦存在时钼蓝法测定磷酸盐的局限性。","authors":"Ruoning Guo, Anna M Röhnelt, Philipp R Martin, Stefan B Haderlein","doi":"10.1007/s00216-025-05850-y","DOIUrl":null,"url":null,"abstract":"<p><p>Organophosphonates (OPs) are widely used as chelating agents in domestic and industrial applications. While regarded as hardly biodegradable, OPs can undergo abiotic transformation with phosphate (PO<sub>4</sub><sup>3-</sup>) as a main transformation product. As some OPs are suspected precursors of glyphosate in surface waters, their environmental fate is of current interest. Due to analytical challenges posed by quantification of individual OPs, monitoring PO<sub>4</sub><sup>3-</sup> formation is a widely used proxy to monitor OP transformations. The molybdenum blue (MB) method, employing UV/Vis spectroscopy, is frequently used for PO<sub>4</sub><sup>3-</sup> quantification due to its sensitivity and operational simplicity. However, while interference of certain inorganic ions is well-documented, the effects of OPs on the accuracy of the MB method remain unexplored. This study investigated the effects of six OPs, namely N-(phosphonomethyl)glycine (glyphosate), 1-hydroxyethylidene(1,1-diphosphonic acid) (HEDP), iminodi(methylene phosphonate) (IDMP), aminotris(methylene phosphonate) (ATMP), ethylenediaminetetra(methylene phosphonate) (EDTMP), and diethylenetriaminepenta(methylene phosphonate) (DTPMP). Spectral analysis of pure PO<sub>4</sub><sup>3-</sup> standards using the MB method exhibits two characteristic absorption maxima (λ<sub>max</sub>) at 710 and 880 nm. In the presence of OPs, a new λ<sub>max</sub> appears around 760 nm. This is accompanied by an increase in absorbance values at both 710 and 880 nm, leading to significant over-quantification of PO<sub>4</sub><sup>3-</sup> concentrations. Among the evaluated OPs, DTPMP exhibits the most substantial interference (PO<sub>4</sub><sup>3-</sup> over-quantification by up to 240%), while glyphosate causes minimal interference (≤ 20%). The effects are most pronounced at OPs:PO<sub>4</sub><sup>3-</sup> ratios ≥1. A case study simulating DTPMP transformation confirms PO<sub>4</sub><sup>3-</sup> over-quantification of up to 350%, revealing limitations of the MB method. Therefore, careful data evaluation and complementary analytical techniques for accurate PO<sub>4</sub><sup>3-</sup> measurements are indispensable in OP transformation research.</p>","PeriodicalId":462,"journal":{"name":"Analytical and Bioanalytical Chemistry","volume":" ","pages":""},"PeriodicalIF":3.8000,"publicationDate":"2025-03-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Limitations of the molybdenum blue method for phosphate quantification in the presence of organophosphonates.\",\"authors\":\"Ruoning Guo, Anna M Röhnelt, Philipp R Martin, Stefan B Haderlein\",\"doi\":\"10.1007/s00216-025-05850-y\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p><p>Organophosphonates (OPs) are widely used as chelating agents in domestic and industrial applications. While regarded as hardly biodegradable, OPs can undergo abiotic transformation with phosphate (PO<sub>4</sub><sup>3-</sup>) as a main transformation product. As some OPs are suspected precursors of glyphosate in surface waters, their environmental fate is of current interest. Due to analytical challenges posed by quantification of individual OPs, monitoring PO<sub>4</sub><sup>3-</sup> formation is a widely used proxy to monitor OP transformations. The molybdenum blue (MB) method, employing UV/Vis spectroscopy, is frequently used for PO<sub>4</sub><sup>3-</sup> quantification due to its sensitivity and operational simplicity. However, while interference of certain inorganic ions is well-documented, the effects of OPs on the accuracy of the MB method remain unexplored. This study investigated the effects of six OPs, namely N-(phosphonomethyl)glycine (glyphosate), 1-hydroxyethylidene(1,1-diphosphonic acid) (HEDP), iminodi(methylene phosphonate) (IDMP), aminotris(methylene phosphonate) (ATMP), ethylenediaminetetra(methylene phosphonate) (EDTMP), and diethylenetriaminepenta(methylene phosphonate) (DTPMP). Spectral analysis of pure PO<sub>4</sub><sup>3-</sup> standards using the MB method exhibits two characteristic absorption maxima (λ<sub>max</sub>) at 710 and 880 nm. In the presence of OPs, a new λ<sub>max</sub> appears around 760 nm. This is accompanied by an increase in absorbance values at both 710 and 880 nm, leading to significant over-quantification of PO<sub>4</sub><sup>3-</sup> concentrations. Among the evaluated OPs, DTPMP exhibits the most substantial interference (PO<sub>4</sub><sup>3-</sup> over-quantification by up to 240%), while glyphosate causes minimal interference (≤ 20%). The effects are most pronounced at OPs:PO<sub>4</sub><sup>3-</sup> ratios ≥1. A case study simulating DTPMP transformation confirms PO<sub>4</sub><sup>3-</sup> over-quantification of up to 350%, revealing limitations of the MB method. Therefore, careful data evaluation and complementary analytical techniques for accurate PO<sub>4</sub><sup>3-</sup> measurements are indispensable in OP transformation research.</p>\",\"PeriodicalId\":462,\"journal\":{\"name\":\"Analytical and Bioanalytical Chemistry\",\"volume\":\" \",\"pages\":\"\"},\"PeriodicalIF\":3.8000,\"publicationDate\":\"2025-03-31\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Analytical and Bioanalytical Chemistry\",\"FirstCategoryId\":\"92\",\"ListUrlMain\":\"https://doi.org/10.1007/s00216-025-05850-y\",\"RegionNum\":2,\"RegionCategory\":\"化学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"BIOCHEMICAL RESEARCH METHODS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Analytical and Bioanalytical Chemistry","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1007/s00216-025-05850-y","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"BIOCHEMICAL RESEARCH METHODS","Score":null,"Total":0}
Limitations of the molybdenum blue method for phosphate quantification in the presence of organophosphonates.
Organophosphonates (OPs) are widely used as chelating agents in domestic and industrial applications. While regarded as hardly biodegradable, OPs can undergo abiotic transformation with phosphate (PO43-) as a main transformation product. As some OPs are suspected precursors of glyphosate in surface waters, their environmental fate is of current interest. Due to analytical challenges posed by quantification of individual OPs, monitoring PO43- formation is a widely used proxy to monitor OP transformations. The molybdenum blue (MB) method, employing UV/Vis spectroscopy, is frequently used for PO43- quantification due to its sensitivity and operational simplicity. However, while interference of certain inorganic ions is well-documented, the effects of OPs on the accuracy of the MB method remain unexplored. This study investigated the effects of six OPs, namely N-(phosphonomethyl)glycine (glyphosate), 1-hydroxyethylidene(1,1-diphosphonic acid) (HEDP), iminodi(methylene phosphonate) (IDMP), aminotris(methylene phosphonate) (ATMP), ethylenediaminetetra(methylene phosphonate) (EDTMP), and diethylenetriaminepenta(methylene phosphonate) (DTPMP). Spectral analysis of pure PO43- standards using the MB method exhibits two characteristic absorption maxima (λmax) at 710 and 880 nm. In the presence of OPs, a new λmax appears around 760 nm. This is accompanied by an increase in absorbance values at both 710 and 880 nm, leading to significant over-quantification of PO43- concentrations. Among the evaluated OPs, DTPMP exhibits the most substantial interference (PO43- over-quantification by up to 240%), while glyphosate causes minimal interference (≤ 20%). The effects are most pronounced at OPs:PO43- ratios ≥1. A case study simulating DTPMP transformation confirms PO43- over-quantification of up to 350%, revealing limitations of the MB method. Therefore, careful data evaluation and complementary analytical techniques for accurate PO43- measurements are indispensable in OP transformation research.
期刊介绍:
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