Capillary electrophoresis for the determination of new markers of natural latex quality.

Nowadays, increasing use of latex products in the healthcare area has also led to an increase in new scientific controls of raw material and manufactured products in order to maintain higher standards in quality control. Since field latex is a rich environment for microbial growth, in the absence of adequate preservation, the carbohydrates that it contains become microbiologically oxidised to the so-called volatile fatty acids (VFAs). Samples of natural rubber latex coming from different countries and processed in different ways have been tested by applying a capillary electrophoresis method for the measurement of the short-chain organic acids present in sera. The separation was performed with phosphate buffer at pH 6.25 and cetyltrimethylammonium bromide (CTAB) as background electrolyte in an uncoated fused-silica capillary with -10 kV of applied potential. The sample needs no other pre-treatment more than coagulation to obtain the serum. In the assayed samples, it has been shown that poorly-preserved latex presented higher amounts of succinic acid and lower amounts of malic acid. The succinic to malic acid ratio may be an important parameter because it cannot be altered by dilution or similar processes such as the traditional VFA index, used to determine the quality of latex. Ratios for succinic to malic acid <0.6 have been found for well-preserved latex and >0.6 for poorly-preserved latex.