Phansi P.Janthama S.Cerdà V.Nacapricha D.Mahidol University2023-06-182023-06-182022-10-01Analytical Sciences Vol.38 No.10 (2022) , 1323-133209106340https://repository.li.mahidol.ac.th/handle/123456789/84157A simple one-step drawing for the cost-effective fabrication of microfluidic paper-based analytical devices (µPADs) for the determination of phosphate content in water and fertilizer samples is presented in this paper. The hydrophobic barrier of µPAD was patterned using a 2-mm tip marker pen using a transparent acrylic sheet template. The molybdenum blue reaction using ascorbic acid as a reducing agent was used. A pre-concentration step of samples is proposed to improve the sensitivity of the measurement. The blue complex produced on the µPADs was recorded using a smartphone camera. The color intensities (red, green, blue and gray) were analyzed using ImageJ program. The proposed µPAD method provides a linear calibration range from 0 to 100 mg L−1 P. The limit of detection (LOD) was found to be 0.7 mg L−1 P with a precision of 3.1%RSD for 50 mg L−1 P (n = 10). The proposed method was successfully applied to the determination of phosphorus contents in water and liquid chemical fertilizer samples. The results obtained from µPAD agreed with a spectrophotometric method using paired t test at a 95% confidence level. Graphical abstract: [Figure not available: see fulltext.].ChemistryArticleSCOPUS10.1007/s44211-022-00162-y2-s2.0-851347702341348224635876988