Paul Giammatteo recently presented two papers at the Gulf Coast conference that was held in Galveston, Texas on January 20-21.

His first paper was entitled “Counting Carbons for Tighter Control: Combining GC and NMR to Improve Distillate Manufacturing” and centers on the topics of Simulated distillation correlated to 1H NMR.

The second paper was entitled “Analytical Data For Engineering Support: Improving the Lab/Process Interface”. This paper details the development of a series of heavy petroleum applications on a Smiths Detection FTIR-ATR spectrometer.

PDFs of the presentations can be obtained from the following links: 1) NMR Talk 2) FTIR-ATR Talk

Alginate is a linear polysaccharide composed of mannuronate (M) and a-L-guluronate (G). The polysaccharide is characterized by the relative ratio of M/G, G-Content, and average length of blocks of G in the polymer. M and G are:

ASTM F2259 recounts the standard sample preparation and 1H NMR analysis that allows the following parameters to be calculated:

The 1H Spectra obtained on a typical alginate sample are show below:

Finally the peaks representing the individual M and G components and sequences are deconvoluted from the spectrum.
The intensities obtained from the deconvolution are input into the excel spreadsheet shown above and the various ratios, M and G content and a series of diads and triads are calculated along with some G block lkength information. It is the block length information that often reveals telling differences between samples.

Process NMR Associates performs this analysis at a cost of $225 per sample. The samples, however, must be prepared by the customer using the methodologt set forth in the test method.

Over the past few years balsamic vinegars have been the subject of a number or NMR studies to determine authenticity, degree of aduleration, and age. 1H NMR has been used to quantify the relative concentrations of a series of organic components (ethanol, fructose, glucose, acetic acid, succinic acid, lactic acid, butandiol, etc (ref 1). 13C NMR has been used to determine the aunthenticity and degree of adulteration (ref 2) as well as the length of the ageing process that a given sample has undergone. Also the formation of glucose and fructose acetates during maturation and ageing has been studied by 1H and 13C NMR.

Refs.
1) Caligiani et al., Anal. Chim. Acta, 585 (2007) 110-119
2) Consonni et al., Talanta, 75 (2008) 765-769
3) Consonni et al., Anal. Chim. Acta, 611 (2008) 31-40
4) Consonni and Caligiani, Talanta, 73 (2007) 332-339
5) Cirlini et al, Food Chemistry, 112 (2009) 51-56

The concentration and distribution of the organic components has been found to correlate well with ageing process analysis, identification of adulteration, and determination of authenticity of traditional balsamic vinegars and balsamic vinegars of Modena.
Below are a series of spectra showing what can chemistry can be quantified in the balsamic vinegars as well as a few comparative spectra of apple cider vinegar and malt vinegar.

For comparison with the home made ciders analyzed in the previous posting I am including the NMR of analysis of a commercial pear cider. The previous ciders were very dry while the pear cider was decidedly sweet. The carbohydrate content is a notable difference. The 1H spectrum is shown with chemical components identified.