Analysis of Total Chloride (MCT) in Palm Oil Matrices

The edible palm oil comes from the fruit of oil palm trees. Two types of oil can be produced, crude palm oil made from the pulp and palm kernel oil made from the kernel in the middle of the fruit. Palm oil is used in all kinds of products, from cookies, margarine, and ice cream, to deodorant, shampoo, toothpaste, and lipstick. This makes palm oil a versatile and critical ingredient in our daily diets and routines.

3-monochloro-1,2-propanediol (3-MCPD) esters are chemical food contaminants that are carcinogenic. The 3-MCPD esters are found in refined, bleached, and deodorized crude palm oil, which is the result of a chemical reaction that takes place at high temperatures in the refining process. The primary precursor for 3-MCPD formation is organic chloride present in the plantation and mill where it gets into the palm oil. Sources of organic chloride are water, fertilizers, pesticides, and soil.

Since 3-MCPD esters are carcinogenic, the World Health Organization has defined a maximum value of the tolerable daily intake for consumers of 2 µg/kg of body weight. Consequently, food producers demand concentrations below 2 ppm in their supplies. Previous studies show a linear dependence between 3-MCPD ester formation and chloride ion concentrations in palm oil.

The Xplorer-TX is perfectly suitable to accurately determine these low concentrations of organic chloride in palm oil matrices.

Method

Palm oil matrices solidify around room temperature due to their melting point. The samples can be introduced in their solid form by the Newton solids autosampler or liquefied by the Archie liquids autosampler equipped with conditioned sample tray. In order to liquefy the samples, the conditioned sample tray is heated at 50 °C. The selected configuration fully complies with all relevant international test methods, such as:

• ASTM D4929
• UOP 779
• ASTM D5808

Results

The results demonstrate the high sensitivity of the Xplorer-TX with relative standard deviations (RSD) well below 5%, regardless of which sampling system is used. The specially developed boat program ensures proper introduction and controlled combustion of samples.

SampleVolumeConc. TX (MCT) – mg/kgRSD (%) n=4
Crude Palm Oil30 µL1.442.59
10 ppm Mineral Oil CRM Std~30 mg9.901.63
Palm Fatty Acid Distillate (PFAD)~30 mg6.661.09
Palm Kernel Fatty Acid Distillate (PKFA)~30 mg2.452.98
Palm Oil Fraction~30 mg2.273.98