Gold nanoparticle mixture retention test with single particle detection: A fast and sensitive probe for functional pore sizes of ultrafiltration membranes

An Efficient Method to Determine Membrane Molecular Weight Cut-Off Using Fluorescent Silica Nanoparticles

“…Therefore, the filtration time was optimized for 2 min to determine the selectivity of the membrane. This is compatible with the duration used in the previous methods which were based on a short time filtration experiment for the determination of the membrane pore size [ 34 ]. This time (2 min) is a compromise between having a sufficient volume of permeate for Nanosight analysis and having a minimum of fouling, in order to limit its impact on the determination of the MWCO.…”

“…Thus, for each NP size tested, the determination of MWCO is affected by the smallest NPs which are blocked in the membrane. So we can deduce that the larger the chosen size, the closer we get to a satisfactory determination of the MWCO as evidenced by the agreement with the manufacturer’s data and a study in the literature [ 34 ]. The same conclusion is obtained for the membrane M2, where the MWCO of the membrane was estimated at 85, 121.5 and 181.5 nm from the retention curves of NPs100-200-300, respectively.…”

“…Furthermore, this old method requires the use of relatively expensive reagents and the precision and robustness of the latter, not yet well proven, in particular by benchmarking against the membranes available on the market. Thus, It is important to choose the mixture of solute to characterize the UF and MF membranes well, since blocking the pores of larger molecules on the surface of the membrane [ 5 , 18 , 27 ], or membrane fouling in forms of retention of large foulants [ 28 , 29 ], droplets deformability [ 30 ], and thermodynamics filtration resistance in gel/cake layer [ 30 , 31 , 32 , 33 ] can potentially selectively impede the transport of different molecular weight solutes, and therefore deflect the MWCO value from the real value [ 34 ]. In most cases, the major factor which does not allow validation of tests, with a single filtration of several components, is the possibility of concentration polarization affecting the membrane filtration [ 34 ].…”

“…Numerous studies tried to find methods to determine the membrane pore size, but until today there has been no consistent method. A recent study, in 2020, used a mixture of gold nanoparticles solutes in a filtrate membrane to determine its pore size qualitatively, although the retention efficiency results are not consistent with 3 out of 5 tested membranes and many questions remain to be answered to understand this phenomenon fully, like why there is higher retention with small gold nanoparticles than with the larger particles [ 34 ].…”

Nanoparticles in analytical laser and plasma spectroscopy – a review of recent developments in methodology and applications

“…The technique was assessed as especially favorable for the fast and sensitive probe for functional pore sizes of ultraltration membranes by investigating the retention of NPs. 398 3.3.6.2. LA-ICP-MS.…”