I would like to recommend that every bioanalytical laboratory purchases Chrom-Matrix PSA bulk material. In the past half years, we had been trying every option (including multi-step SPE cleanup) to develop a GLP bioanalytical method for LC-MS/MS   

    determination of paclitaxel in swine liver without a success. The sponsor got very mind against us. Finally, I followed Chrom-Matrix’s recommendation to add PSA into MTBE extraction. Just by one step of sample pre-treatment, I got the three core runs passed. I saw a majority of yellow substances removed by PSA. The validation passed!!!