The invention belongs to the field of
analytical chemistry, and particularly relates to a method for analyzing a
phosphate detection sample in food, especially aquatic products. The method realizes high-efficiency detection of
phosphate through combination of
water extraction and XRF, and comprises the following steps:
sample preparation and extraction: unfreezing a frozen
aquatic product, then carrying out high-speed crushing at a speed of 22000 r / min, carrying out vortex mixing on an
aqueous solution, carrying out ultrasonic extraction for 3-15 min, carrying out centrifugal treatment at a speed of 8000 r / min, and taking a supernatant; establishing a matrix labeling
standard curve: adding a
sodium phosphate standard substance (0-529.14 mg) into the sample, extracting to obtain a standard working solution with the
phosphorus content of 600-20600 mg / kg, and establishing the matrix labeling
standard curve by using XRF (X-
Ray Fluorescence) intensity and
phosphorus concentration; and XRF analysis: detecting the sample for 5 minutes under the conditions that the tube pressure is 10 kV, the tube flow is 100 [mu] A and the analysis
spectral line is
K alpha (2.010 keV), and calculating the
phosphorus content according to the curve. Compared with traditional detection, detection can be completed only in 15 min based on XRF, and the speed is increased by 16-40 times. The pretreatment only needs
water extraction, chemical reagents are avoided, the accuracy is remarkably improved by using a matrix
standard curve, and the method is suitable for
quality monitoring of frozen aquatic products.