Quantitative extraction of sulfonamides in meats by supercritical methanol-modified carbon dioxide: A foray into real-world samplingOptimizing operational parameters and obtaining the highest possible recovery are two of the major objectives to be attained when any extraction process is performed on a real sample in which the true analyte concentration is unknown. Sulfadiazine (SDZ), sulfamerazine (SMR), and sulfamethazine (SMZ) were extracted from real samples of chicken liver, beef liver, and pig kidney, using methanol-modified supercritical CO 2 . The optimum extraction parameters were found to be 17.237 MPa and 1608C for two of the three analytes; SMZ, on the other hand, was completely extracted at 1208C. Under these conditions of high temperature, high amounts of modifier (3.0 mL of methanol in a 10-mL extraction vessel) and low pressure, all three sulfonamides (SAs) were shown to be quantitatively extracted from spiked samples from domestic animals which had not been given sulfonamides. Under the same conditions, meat samples of commercial origin were analyzed. These results were compared with those obtained by conventional extraction methods. Almost all the meat samples contained sulfa drug residue levels far exceeding the current tolerance levels allowed for most sulfonamides. Eighteen of thirty samples contained at least one of the three sulfonamides, and seven of these samples contained from 1.1 to 4.2 mg kg -1 of SMZ. The SAs were quantified by HPLC with UV absorbance and amperometric detection.

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