ABSTRACT
In environmental analysis, the detection of water-soluble synthetic polymers (WSSP) presents considerable challenges. Thus, a precise and reproducible analytical method was developed using continuous-flow off-line pyrolysis with gas chromatography/mass spectrometry (GC/MS) to simultaneously identify multiple water-soluble polymers from a single environmental sample. WSSP are widely used in multiple industries as hydrogels due to their hydrophilic character and potential biocompatibility. This adaptability of hydrogels is reflected in their ability to provide customized formulations for specific needs, such as in the development of personal care products, medicine, and pharmaceuticals. Specifically, polyvinylpyrrolidone (PVP), poly(N-vinylcaprolactam) (PNVCL), and polyethyleneimine (PEI) were targeted for analysis in wastewater, employing unique pyrolysis products for identification. These polymers require careful assessment in wastewater to evaluate potential environmental risks associated with their release. PVP and PNVCL were identified through two pyrolysis products, while six pyrolysis products were utilized for the identification of PEI. The validated method demonstrated very good linearity and reproducibility, with correlation coefficients ranging from 0.94 to 0.99 and relative standard deviation (RSD) values between 3 % and 36 % for the targeted compounds. The limit of quantification (LOQ) for the three polymers ranged from 1 to 10 µg L-1. Moreover, the average recovery rates for these polymers, determined from artificial water samples, were approx. 85 %. Utilizing the validated method, water samples from seven wastewater treatment plants in Germany were successfully analyzed, confirming the presence of these polymers at elevated concentrations in the µg L-1 range. Notably, untreated influent waters exhibited higher polymer levels compared to treated influents and effluents, underscoring their significant contribution to overall polymer content. The developed analytical method provides an efficient tool for the simultaneous identification and quantification of PVP, PNVCL, and PEI in wastewater samples. The results highlighted the prevalent presence of PVP, PNVCL, and PEI in the tested wastewater samples, indicating their significant abundance.
ABSTRACT
The quotes of the Negro River are measured every day since September 1902 until today. This work is based on the years 1903 until 1999. The five highest flooding happened in: 1953 (29,69m), 1976 (29,61m), 1989 (29,42m), 1922 (29,35m) and 1909 (29,17m). The five lowest floding happened in: 1963 (13,65m), 1906 (14,20m), 1997 (14,34m), 1916 (14,42m) and 1926 (14,54m). The five smaller values of maximum quotas were em: 1926 (21,77m), 1912 (24,84m), 1992 (25,42m), 1964 (25,91m) and 1980 (26,00m) and the five of minimum quotas were in: 1926 (21,77m), 1912 (24,84m), 1992 (25,42m), 1964 (25,91m) and 1980 (26,00m). The five larger differences reached in a same year among the maximum and minimum quotas happened in: 1997 (14,62m), 1909 (14,13m), 1953 (12,62m), 1952 (12,44m) and 1916 (12,21m). And the smallest ones happened in: 1912 (05,45m), 1968 (06,10m), 1985 (06,53m), 1974, (06,62m) and 1986 (06,74m).
As cotas do rio Negro vem sendo medidas, diariamente, desde setembro de 1902. O presente trabalho baseou-se em dados colhidos entre os anos de 1903 a 1999. As cinco maiores enchentes aconteceram em: 1953 (29,69m), 1976 (29,61m), 1989 (29,42m), 1922 (29,35m) e 1909 (29,17m). As cinco maiores vazantes aconteceram em: 1963 (13,65m), 1906 (14,20m), 1997 (14,34m), 1916 (14,42m) e 1926 (14,54m). Os cinco menores valores de cotas máximas foram em: 1926 (21,77m), 1912 (24,84m), 1992 (25,42m), 1964 (25,91m) e 1980 (26,00m) e os cinco de cotas mínimas foram em: 1926 (21,77m), 1912 (24,84m), 1992 (25,42m), 1964 (25,91m) e 1980 (26,00m). As cinco maiores diferenças alcançadas em um mesmo ano entre as cotas máximas e mínimas aconteceram em: 1997 (14,62m), 1909 (14,13m), 1953 (12,62m), 1952 (12,44m) e 1916 (12,21 m) e as menores aconteceram em: 1912 (05,45m), 1968 (06,10m), 1985 (06,53m), 1974, (06,62m) e 1986 (06,74m).
