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Lots of other interesting compounds were found like detergents, surfactants, emulsifiers, plasticisers, fatty acids and hydroxy fatty acids, along with anthelmintics and fungicides/herbicides. There were also a lot of plant-based metabolites (lots of different terpenoids), along with bile acids.

Untargeted LC-MS analysis More detailed screening found more than 25,000 different chemicals, including the herbivore faecal marker (ethylcoprostanol), unlike the Coogee beach ones as they only contained the human faecal matter biomarker.

Mass spectrometry The negative ion mass spectrometry revealed a sequence of masses separated by 28 mass units, consistent with a difference of 2 CH2 units. This is consistent with a biological source.

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Also a pretty good match to the spectrum predicted by MNova

In the 13C NMR we observe a single peak at 174 ppm, consistent with a carboxylic acid carbonyl carbon. Then a signal at 33.7 ppm consistent with a CH2 adjacent to a carbonyl group, and a series of CH2 signals (confirmed by 1H-13C HSQC) between 31 and 21 ppm, and finally a CH3 group down at 14 ppm.

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Both the 1H and 13C NMR (and some 2D spectra like HSQC and TOCSY) confirm the sample that dissolves in DMSO is mostly a saturated aliphatic fatty acid. In the 1H we can see a series of signals, including an exchangeable proton likely to be an OH group of a carboxylic acid...

NMR Small samples of the untreated balls, and of the DCM extract, were dissolved in DMSO-d6 for NMR analysis. MOST of it dissolves...

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FTIR Next we did some FTIR on some of the extracts and found signals that correspond to C-H groups, and C=O groups. From the DCM and hexane extracts contain more free COOH than the residue after washing, which looks like just salts of fatty acids.

XRF Using X-ray Fluorescence spectroscopy we could detect elements heavier than sodium in the sample. We found minimal sodium, but a lot of calcium, and some phosphorus and iron. These are relative %, not the total composition.

Elemental Analysis We took the balls and tried to dissolve them in organic solvents (DCM and hexane), and removed the water-soluble fraction. We then analysed the samples either as the raw balls from the beach (raw), the DCM extract, and the residue after washing with DCM then hexane (hex).

Melting Point We also measured the melting point of the untreated balls, and found they have a melting point of around 50 degrees, and the sample is completely melted by 83 degrees:

Here is an extraction with DCM, drying over MgSO4, and evaporated to give an oil that solidified on cooling

The balls are mostly around the diameter of a 5c coin. They float on water, and the organic solvents we sonicated then extracted them with (DCM and hexane)

Sydney North Shore beach balls - @unswchemistry.bsky.social analysed them! TL,DR: filthy soap scum. Details below! #tarballs #grimeballs #ozchem

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Mass spectrometry - The negative ion mass spectrometry revealed a sequence of masses separated by 28 mass units, consistent with a difference of 2 CH2 units, consistent with a biological source. The exact mass reveals the largest peak at 255.24 - the palmitate anion, derived from palmitic acid

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