ISO 19619:2018 pdf free
ISO 19619:2018 pdf free.Surface active agents
Weigh about 1,0 g (accurate to 0,1 mg) of the test sample (8.1) and add it to each of three separate headspace sample vials (6.3). Then, add 5 ml of DMAC (5.3), to each of the vials. Seal each vial, and after 2 min vortexing homogenization, put it in the headspace sampler and conduct the test.
NOTE The above processing procedure is suitable for liquid paste or solid samples while liquefaction and homogenization is necessary for some samples with poor aqueous solubility and low dissolution. In principle, the sample preparation methods for solid substances can be accelerated by gentle warming or by heating the solvent (below 50 °C).
Under the chromatographic and mass spectrometer conditions given below (see Clause 9), identify the propylene oxide based on the retention times. If the retention time of chromatographic peak is consistent with that of standard propylene oxide, the occurrence of selected ions in sample mass spectra is confirmed after the deduction of background, and the relative abundance ratio of detect ion is consistent with that of the standard sample shown in Table 2 and Table 3, the presence of propylene oxide in sample is determined.
Using the propylene oxide standard solution (7.2), establish a standard calibration curve. Test the samples by headspace chromatography procedure and calculate the analyte level in sample based on the concentration measured according to the corresponding linear regression equations and peak areas.
Prepare a calibration curve by plotting the propylene oxide peak areas on the ordinate (Y-axis) versus content for the propylene oxide component on the abscissa (X-axis). Extrapolate the line to the point where it intercepts the abscissa (see Figure 1). This intersection is the propylene oxide content of the sample.
When calculating the results in accordance with the standard addition procedure, the calibration curve should be rectilinear and the correlation coefficient should be 0,995 or better. The standard deviation of the values at the intercept shall not exceed a 10 % of the mean value. Or else, prepare the new solutions and determine again. If necessary, add 1 or 2 determination points.ISO 19619 pdf download.
