Determination of Acrylic Acid in Solid Waste by Gas Chromatography-Mass Spectrometry with Microwave Extraction

After the sample was collected refer to HJ/T 20-1998, impurities in which were removed. Refering to HJ 765-2015, easily ground sample was ground or crushed, and passed through sieve with pore diameter of 1 mm, and the sample that was not easy to grind was cut and torn, so that it could be fully soaked in the extraction solvent. An aliquot (5.000 g) of sample was taken, and 2.000 g of anhydrous sodium sulfate and 2.000 g of diatomaceous earth were added. After mixing well, 20 mL of acetone was added, and microwave extraction was made at 80℃ for 15 min. The digestion solution was cooled to room temperature, and 5.000 g of anhydrous sodium sulfate was added to remove water. The mixture was filtered using qualitative filter, and the filtrate was place into a nitrogen blowing tube, and its volume was concentrated to about 1 mL below 35℃. The solution was quickly passed through the magnesium silicate solid phase extraction column. Using 1 mL of acetone to wash the nitrogen blowing tube 3 times, all the washing solution was passed through the column, and 15 mL of trichloromethane-acetone mixed solution at volume ratio of 1:1 was added for elution. The eluate was collected, and its volume was continually concentrated to about 0.5 mL under nitrogen blowing conditions below 35℃. An aliquot (5 μL) of 1 000 mg·L^-1 1,4-dichlorobenzene-d₄ internal standard solution was added into the above concentrate, and the mixed solution was diluted to 1.0 mL by acetone, and introduced into gas chromatograph-mass spectrometer. Acrylic acid was separated under temperature programmed conditions on the DB-FFAP chromatographic column, ionized by the EI source, detected by the SIM mode, and quantified by internal standard method. It was shown that linear relationship between values of the mass concentration of acrylic acid and the respective MS response value ratio was kept in the range of 0.5-20.0 mg·L^-1, with detection limit (3.143s) of 0.08 mg·L^-1. The spiked recovery test was made on negative industrial ash and biochemical sludge at the 3 concentration levels, giving recoveries ranging from 68.5% to 90.1%, and RSDs (n=6) of the determined values were in the range of 2.6%-9.1%.