3.2.9.7. Conclusion

Nephelometry and turbidimetry are almost always carried out in batch format, where each sample is assigned to its own container with a volume of anywhere between 0,1 and 10 mL. In contrast, flow-based methods, where samples are sequentially analyzed while they travel through a tubular conduit, are seldom used to automate nephelometry or turbidimetry. According to Hansens Database, the first paper on Flow Injection Turbidimetry was published in 1977 by a group from Brazil (F. J. Krug, et.al, Analyst,102 (1977) 503 on the determination of sulphate precipitated by barium chloride. Since then, over 24.000 papers were published on various FIA related topics, but only ten (10!) on FI turbidimetry (or nephelometry), all of them based on precipitation reactions, and none of them, as far as we could find, on the determination of Suspended Matter.

We believe that by reexamining the scope of Beer’s law will highlight the hidden link between Flow Injection turbidimetry and spectrophotometry and show how programmable Flow Injection [9] can be used to investigate limits of our Knowledge.
 

References:

[1] Mariko Hatta, Jaromir Ruzicka, Christopher I. Measures “The performance of a new linear light path flow cell is compared with a liquid core waveguide and the linear cell is used for spectrophotometric determination of nitrite in sea water at nanomolar concentrations. “ Talanta 219 (2020) 1212
[2] Mariko Hatta, Jaromir Ruzicka, Christopher I. Measures, Madeline Davis “Autocalibration using a single standard  solution prepared in deionized water is applied to determination of nutrients in sea water by programmable flow injection “ Talanta 253(2023) 124041
[3] E.A. Nagul, I.A. McKevie, P. Worsfold, S.. Kolev “The molybdenum blue reaction for the determination of orthophosphate revisited: Opening the black box” Anal. Chim. Acta. 890 (2015) 60-82
[4]  J. Ruzicka, G. D. Marshall, Ch. Measures, M. Hatta“ Flow injection programmed to function in batch mode is used to determine molar absorptivity and to investigate the phosphomolybdenum blue method “Talanta 201 (2019) 519–526
[5] Mariko Hatta, Jaromir Ruzicka, Christopher I. Measures, Madeline Davis “Autocalibration based on a single concentrated standard is used or the determination of silica in sea water by the modified molybdenum blue method “Talanta 276 (2024) 126
[6] Pierre Bouguer, “Essai d'optique, sur la gradation de la lumière” (in French) Paris. Claude Jombert (1729) 164 pages.
[7] Johann Heinrich Lambert „Photometria, sive de mensura et gradibus luminis, colorum et umbrae“ Augsburg: Eberhard Klett, (1760) 547 pages
[8] August Beer „Bestimmung der Absorption des rothen Lichts in farbigen Flüssigkeiten“ (in German) Annalen der Physik (1852) 78.
[9] Jaromir Ruzicka, Petr Chocholous, “Next generation of flow analysis is based on flow programming” Talanta 269 (2024) 125410
 

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