A small-scale neutral alumina column chromatography method for carbon isotope determination of hopanes in crude oils or rock extracts.

This paper presents a small-scale column chromatography method for separating hopanes in crude oil or rock extracts using neutral alumina as a solid phase adsorbent and a Pasteur pipette as a separation device. Three oil samples were selected to study the effect of solid phase adsorbent type and column length on the separation of hopanes. The oil samples were eluted with mixed reagents (V hexane: V petroleum ether = 8:2) and collected at intervals of 0.5 ml. Ten Fractions were collected and tested for the compounds using GC-MS. A quantitative approach was used to reveal distribution characteristics of compounds in each eluted Fraction. Experimental results showed that 100-200 um neutral alumina exhibited significant differences in the adsorptive capacity of biomarkers from oil samples and rock extracts. The elution order of the biomarkers in the chromatographic column (the length is 180 mm) was n-alkanes, steranes and hopanes. The separation of hopanes could be realized by collecting the eluted Fractions 4 and 5. Compared with the urea complexation, the purity of hopanes separated by column chromatography was higher. The concentration of n-alkanes (nC16-nC34) could be reduced from 1.99 to 4.83 mg/ml to 0.79-0.94 mg/ml, and the content of steranes can be reduced from the original 12% to 0.45%. Residual n-alkanes and steranes were not visible in the GC-MS detection. The Total Ion Chromatography (TIC) of hopanes was consistent with the distribution characteristics of the m/z191 mass chromatogram. The isolated hopanes could meet the detection requirements of isotope ratio mass spectrometry. The C29Ts/C29αß ratio of hopanes decreased gradually from 1.63 to 0.73 as the column length increased. It is speculated that the variation of the C29Ts/C29αß ratio is not only affected by maturity but also by the oil and gas migration. This method is a new attempt in the field of compound purification and can be widely used in the study of stable carbon isotopes of hopanes monomeric hydrocarbons.

Effect of Using the Modified Milch Technique on Quality of Life in Patients with Anterior Dislocation of the Shoulder Joint.

Objective: To evaluate the effect of the Milch technique on quality of life (QoL) in patients with anterior dislocation of the shoulder joint. Methods: A total of 126 patients undergoing manual reduction for anterior dislocation of the shoulder in our hospital from January 2021 to January 2022 were prospectively enrolled in this study. The randomized number table method was used to divide patients into the study group (63 patients) and the control group (63 patients). The study group was treated with a modified Milch technique while the control group was treated with the Hippocratic method. Success rate and complications were compared to evaluate the effectiveness of manual reduction. Clinical assessment of shoulder function included the Constant-Murley Score and visual analog scale (VAS) before, during and after manual reduction. Results: The success rate of primary and secondary reduction in the study group was significantly higher than in the control group (87.30% vs 61.90, respectively; P = .001; 11.11% vs 25.40%, respectively; P = .038). The failure rate in the study group was significantly lower than in the control group (1.59% vs 12.70%, respectively; P = .015). The time required for reduction in the study and control groups was 58.87 ± 7.92 seconds and 93.09 ± 8.01 seconds, respectively; a significant difference (t = -24.113; P < .001). There was no statistically significant difference in VAS scores before and during reduction in the 2 groups. After reduction, VAS scores in the study group were significantly lower than in the control group (1.02 ± 0.01 vs 1.14 ± 0.26, respectively; P < .001). There were no significant differences in pain level, activities of daily living, joint range of motion or muscle strength between the 2 groups before and after reduction (P > .05). After reduction, health status, emotional function, mental health, physiological function, physiological function, physical pain, vitality and social function scores in the study group were significantly higher than in the control group (P < .05). There were 4 avulsion fractures and 2 humeral fractures in the control group; no complications occurred in the study group, with a significant difference (χ2 = 6.289; P = .012). Conclusion: The Milch technique can improve the QoL in patients with anterior dislocation of the shoulder, and the success rate of the reduction is high.