Screening of preservatives by HPLC-PDA-ESI/MS: A focus on both allowed and recently forbidden compounds in the new EU cosmetics regulation.

Commission regulation (EU) No 358/2014 amending the new regulation (EC) No 1223/2009 on cosmetics has prohibited the use of isopropyl-, isobutyl-, phenyl-, benzyl- and pentylparaben. Furthermore, Commission regulation (EU) No 1004/2014 has lowered the maximum permitted concentration of butyl- and propylparaben in cosmetics and it has also banned them in leave-on products designed for application on the nappy area of children under three years of age. A HPLC-PDA-ESI/MS method has been developed herein for the detection of seventeen preservatives, both the most utilised and the recently forbidden by the new EU regulations. The separation of these compounds, including benzoic acid and its derivatives in a 1.10 - 3.04 log Pow range, has been performed with a gradient elution on a Symmetry(®) C18 column (250×4.6mm i.d., particle size 5µm) with water and acetonitrile (0.1% formic acid) as mobile phase. Quantification has been carried out by HPLC-PDA. The method has been validated and successfully applied to the analysis of a large number of cosmetics with different functions like rinse-off and leave-on, or composition like skin, hair, face and oral products.

LC-MS Determination of remifentanil in maternal and neonatal plasma.

An HPLC-MS with electrospray ionization method for the determination of remifentanil in human plasma samples, pre-treated with SPE cartridge, has been developed and validated. Ionisation was performed by positive-ion electrospray and quadrupole filter mass spectrometer operated in the single ion-recording mode. Pre-treatment was performed using Waters Oasis((R)) SPE cartridges. Chromatographic separation was achieved in isocratic elution using a X-Terra C8 5 microm, 150 mm x 2.1 mm i.d. column. The mobile phase consisted of a mixture of water, methanol and acetonitrile (86:10:4, v/v/v) containing 0.1% of formic acid. The method showed to be linear in the range between 0.5 and 48.0 ng/ml, the estimated LOD is 0.18 ng/ml and the LOQ is 0.5 ng/ml. The method can be used to quantify remifentanil in plasma samples taken from adult and newborn patients in a range suitable for clinical studies.

LC-MS determination of MPTP at sub-ppm level in pethidine hydrochloride.

An HPLC-MS with electrospray ionisation method for the determination of MPTP at sub-ppm level in pethidine hydrochloride has been developed and validated. Ionisation is performed by positive-ion electrospray and the quadrupole filter mass spectrometer is operated in the single ion recording mode. Chromatographic separation was achieved in gradient elution using a symmetry C18, 5 microm, 150 mm x 2.1 mm i.d. The mobile phase comprised water containing 0.1% formic acid (v/v) and acetonitrile containing 0.1% formic acid (v/v). The method showed to be linear in the range between 0.2 and 2.2 ng/ml, the estimated LOD was lower than 0.1 ng/ml and the LOQ was lower than 0.2 ng/ml.