Objective The aim of this study was to develop a method for the determination of nine vulcanizing agents and accelerators in pharmaceutical rubber stoppers by headspace gas chromatography with sulfur chemiluminescence detector(HS-GC-SCD).Methods A DB-1 capillary column(30 m×0.32 mm×0.25 μm)was used with He as the carrier gas.The injection port temperature was 220 ℃,the split ratio was 10∶1,and the carrier gas flow rate was 1.5 mL·min-1.The temperature program was as follows:the starting temperature was 40 ℃,and it was increased to 60 ℃ at a rate of 5 ℃ per minute,and then to 260 ℃ at a rate of 15℃per minute.SCD detector parameters:base temperature was 280℃,combustion chamber temperature was 800 ℃,air flow rate was 60 mL·min-1,and hydrogen flow rate was 40 mL·min-1.Results The sample pretreatment method was simple and convenient,and it effectively reduced the extraction loss.The methodological results showed that all sulfides showed good linear relationships within the concentration range(r2≥ 0.990).The RSD was less than 2％;and the average recovery rate was 86.4％-97.5％.From the analysis of the sample test results,free sulfur is commonly found in rubber stoppers.Among all the samples of the vulcanization system,the free sulfur detected in the sulfur vulcanization system is higher than the free sulfur produced by degradation of other vulcanization systems.Conclusions This method is simple to operate,compared with other existing detection methods.HS-GC-SCD has a smaller matrix effect,higher sensitivity and selectivity,and is appropriate for quantifying the concentrations of sulfide present in various rubber stoppers.

Objective The aim of this study was to develop a method for the determination of nine vulcanizing agents and accelerators in pharmaceutical rubber stoppers by headspace gas chromatography with sulfur chemiluminescence detector(HS-GC-SCD).Methods A DB-1 capillary column(30 m×0.32 mm×0.25 μm)was used with He as the carrier gas.The injection port temperature was 220 ℃,the split ratio was 10∶1,and the carrier gas flow rate was 1.5 mL·min-1.The temperature program was as follows:the starting temperature was 40 ℃,and it was increased to 60 ℃ at a rate of 5 ℃ per minute,and then to 260 ℃ at a rate of 15℃per minute.SCD detector parameters:base temperature was 280℃,combustion chamber temperature was 800 ℃,air flow rate was 60 mL·min-1,and hydrogen flow rate was 40 mL·min-1.Results The sample pretreatment method was simple and convenient,and it effectively reduced the extraction loss.The methodological results showed that all sulfides showed good linear relationships within the concentration range(r2≥ 0.990).The RSD was less than 2％;and the average recovery rate was 86.4％-97.5％.From the analysis of the sample test results,free sulfur is commonly found in rubber stoppers.Among all the samples of the vulcanization system,the free sulfur detected in the sulfur vulcanization system is higher than the free sulfur produced by degradation of other vulcanization systems.Conclusions This method is simple to operate,compared with other existing detection methods.HS-GC-SCD has a smaller matrix effect,higher sensitivity and selectivity,and is appropriate for quantifying the concentrations of sulfide present in various rubber stoppers.

The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system, belonging to the type II CRISPR/Cas system, is an effective gene-editing tool widely used in different organisms, but the size of Streptococcus pyogenes Cas9 (SpCas9) is quite large (4.3 kb), which is not convenient for vector delivery. In this study, we used a codon-optimized Staphylococcus aureus Cas9 (SaCas9) system to edit the tyrosinase (tyr), oculocutaneous albinism II (oca2), and paired box 6.1 (pax6.1) genes in the fish model medaka(Oryzias latipes), in which the size of SaCas9 (3.3 kb) is much smaller and the necessary protospacer-adjacent motif (PAM) sequence is 5'-NNGRRT-3'. We also used a transfer RNA (tRNA)‍-single-guide RNA (sgRNA) system to express the functional sgRNA by transcription eitherin vivo or in vitro, and the combination of SaCas9 and tRNA-sgRNA was used to edit the tyr gene in the medaka genome. The SaCas9/sgRNA and SaCas9/tRNA-sgRNA systems were shown to edit the medaka genome effectively, while the PAM sequence is an essential part for the efficiency of editing. Besides, tRNA can improve the flexibility of the system by enabling the sgRNA to be controlled by a common promoter such as cytomegalovirus. Moreover, the all-in-one cassette cytomegalovirus (CMV)‍-SaCas9-tRNA-sgRNA-tRNA is functional in medaka gene editing. Taken together, the codon-optimized SaCas9 system provides an alternative and smaller tool to edit the medaka genome and potentially other fish genomes.
Animals ; Oryzias/genetics* ; Gene Editing/methods* ; CRISPR-Cas Systems ; Codon ; RNA, Guide, CRISPR-Cas Systems/genetics* ; Monophenol Monooxygenase/genetics* ; CRISPR-Associated Protein 9/genetics* ; RNA, Transfer/genetics* ; Staphylococcus aureus/genetics* ; PAX6 Transcription Factor/genetics*