Color Index Disperse Yellow 42 (DY42), a high-volume disperse dye for polyester, was used to compare the capabilities of the LTQ-Orbitrap XL and the LTQ-FT-ICR with respect to mass measurement accuracy (MMA), spectral accuracy, and sulfur counting. The results of this research will be used in the construction of a dye database for forensic purposes; the additional spectral information will increase the confidence in the identification of unknown dyes found in fibers at crime scenes. Initial LTQ-Orbitrap XL data showed MMAs greater than 3 ppm and poor spectral accuracy. Modification of several Orbitrap installation parameters (e.g., deflector voltage) resulted in a significant improvement of the data. The LTQ-FT-ICR and LTQ-Orbitrap XL (after installation parameters were modified) exhibited MMA ≤ 3 ppm, good spectral accuracy (chi-square values for the isotopic distribution ≤ 2), and were correctly able to ascertain the number of sulfur atoms in the compound at all resolving powers investigated for AGC targets of 5.00×105 and 1.00×106.

Methodology is presented for the rapid analysis of drugs of abuse using a single UHPLC column with orthogonal separation methods using different combinations of the same solutions in the solvent reservoir.

BackgroundChlamydia retesting three months after treatment is recommended to detect reinfections, but retesting rates are typically low. The REACT (retest after Chlamydia trachomatis) randomised trial demonstrated that home-based retesting using postal home-collection kits and SMS reminders, resulted in substantial improvements in retesting rates in women, heterosexual men and men who have sex with men (MSM), with detection of more repeat positive tests compared with SMS reminder alone. In the context of this trial, the acceptability of the home-based strategy was evaluated and the costs of the two strategies were compared.MethodsREACT participants (200 women, 200 heterosexual men, 200 MSM) were asked to complete an online survey that included home-testing acceptability and preferred methods of retesting. The demographics, sexual behaviour and acceptability of home collection were compared between those preferring home-testing versus clinic-based retesting or no preference, using a chi-square test. The costs to the health system of the clinic-based and home retesting strategies and the cost per infection for each were also compared.ResultsOverall 445/600 (74 %) participants completed the survey; 236/445 from the home-testing arm, and 141 of these (60 %) retested at home. The majority of home arm retesters were comfortable having the kit posted to their home (86 %); found it easy to follow the instructions and collect the specimens (96 %); were confident they had collected the specimens correctly (90 %); and reported no problems (70 %). Most (65 %) preferred home retesting, 21 % had no preference and 14 % preferred clinic retesting. Comparing those with a preference for home testing to those who didn’t, there were significant differences in being comfortable having a kit sent to their home (p = 0.045); not having been diagnosed with chlamydia previously (p = 0.030); and living with friends (p = 0.034). The overall cost for the home retest pathway was $154 (AUD), compared to $169 for the clinic-based retesting pathway and the cost per repeat infection detected was $1409 vs $3133.ConclusionsAmong individuals initially diagnosed with chlamydia in a sexual health clinic setting, home-based retesting was shown to be highly acceptable, preferred by most participants, and cost-efficient. However some clients preferred clinic-based testing, often due to confidentiality concerns in their home environment. Both options should be provided to maximise retesting rates.Trial registrationThe trial was registered with the Australia New Zealand Clinical Trials Registry on September 9, 2011: ACTRN12611000968976.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-016-2727-4) contains supplementary material, which is available to authorized users.

Dyed fibers are commonly obtained as trace evidence at crime scenes. Time-of-flight mass spectrometry (TOF MS) has potential to substantially advance forensic dyed fiber analysis by providing "exact mass" data of dyes and other chemicals present in dyed fibers. Data from two approaches to using TOF MS for accurately identifying the molecular formula of dyes are reported. One involves extraction of dye from 100 μg or less of fiber followed by high performance liquid chromatography (HPLC-TOF MS) analysis. The other is time-of-flight secondary ion mass spectrometric (TOF SIMS) analysis of the surface and cross sections of dyed fibers without extraction. Both approaches can clearly identify commercially important dyes applied to polyester fibers.