Drug abuse still represents a global problem, and it is associated with an increased risk of diseases, injuries, and deaths. Cocaine (COC) and opiates are the most abused drugs and account for a significant number of fatalities. Therefore, it is important to develop methods capable of effectively identifying and quantifying these substances. The present study aims to evaluate the long-term stability of COC, ecgonine methylester (EME), benzoylecgonine (BEG), cocaethylene (COET), norcocaine (NCOC), morphine (MOR), codeine (COD) and 6-monoacetylmorphine (6-MAM) in oral fluid samples. The analytes of interest were isolated from the matrix (50 µL) using the dried saliva spots (DSS) sampling approach and were subsequently analyzed by gas chromatography coupled with tandem mass spectrometry (GC–MS/MS). The parameters that could influence the stability of the target compounds were studied, and these were storage temperature, light, use of preservatives (and respective concentrations), and time. The effects of each parameter were evaluated using the design of experiments (DOE) approach. The stability of the target analytes was improved when the DSS were stored at room temperature, in the presence of light and using 1% sodium fluoride. The best conditions were then adopted for the DSS storage and long-term stability was assessed. COD was only stable for 1 day, EME was stable for 3 days, COC, COET, NCOC and 6-MAM were stable for 7 days, MOR for 14 days and BEG remained stable throughout the study (136 days). This is the first study that evaluates the stability of these compounds in oral fluid samples after application in DSS cards, and optimizes the conditions in order to improve their stability.

It is common knowledge that natural dyes are fit for textile dyeing since ancient times. Basically, natural dyes are elements derived from natural resources, and classified as plant, animal, mineral, and microbial dyes based upon their source of origin. Natural dyeing is a very important part of the old Portuguese tradition which is, currently, regaining awareness due to sustainability and health issues that has arisen from the massive application of synthetic dyes in textile coloration. In this study we sought to optimize the extraction of Sorghum vulgare (curumanine and apigeninidin) through the use of a design of experiments (DOE) methodology and to develop an analytical method by high performance liquid chromatography-diode array detector (HPLC-DAD) for their quantification. Dyes extracted and isolated were then used to dye 100% wool jersey knits by way of the exhaustion process. The color strength and fastness properties of the dyed samples against washing, and rubbing were evaluated. Our findings proved that meta-mordanted samples dyed at 80°C for 4h obtained the best strength and color fastness results.