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This study selected five typical types of chemical industry volatile organic compounds (VOCs) emission characteristics in China for analysis. The results from 70 source samples showed that alkanes were the dominant VOCs category from synthetic material industry sources, petrochemical industry sources, and coating industry sources (accounting for 43%, 63%, and 68%, respectively); olefins were the main VOCs category from the daily supplies chemical industry (46%); and halogenated hydrocarbons were the dominate VOCs category from specialty chemicals industry account source emissions (43%). Additionally, the machine learning method was applied in this study to analyze the marker components of the above industries. The results showed that decane and tetrahydrofuran were the source markers of the synthetic material industry; n-butanol and toluene were the markers of the daily supplies industry source; 1,2,3-trimethylbenzene and 1,3,5-trimethylbenzene were the markers of the petrochemical industry source; propylene and 3-methyl pentane were the source markers of the coating industry; and P-Xylene and cumene were the markers of the specialty chemicals industry source. The maximum incremental reactivity method (MIR) was used to estimate the ozone formation potential (OFP) of different VOCs-sources. The calculation results showed that when considering per unit TVOCs concentration emissions, the contribution to the ozone generation potential was in the order of the daily supplies chemical industry, specialty chemical industry, petrochemical industry, synthetic material industry, and coating industry. Therefore, we suggest that more attention should be paid to the key active species emitted by various industry sources rather than only the total amount of VOCs emissions in future ozone prevention and control efforts.

In order to explore the characteristics of exhaust gas emissions, environmental impact, and human health risks in the pesticide manufacturing industry, two typical pesticide manufacturing enterprises were selected as the research objects, and samples were collected and analyzed for all exhaust pipes of each enterprise. The following results were noted:there were certain differences in the pollutants produced by different enterprises due to different products and production links. The main pollutants in enterprise A were ammonia and VOCs. The concentration of ammonia in enterprise A ranged from 0 to 847.83 mg·m -3 , and the concentration of VOCs ranged from 4.21 to 91.68 mg·m -3 . The main pollutants in enterprise B were VOCs, and the concentration of VOCs ranged from 3.37 to 197.30 mg·m -3 . The ozone formation potential (OFP) ranged from 1.96 to 107.24 mg·m -3 . Substances that required further attention in terms of ozone formation potential:enterprise A mainly included ethanol, methanol, toluene, xylene, and other substances; enterprise B mainly included 1, 1-dichloroethylene, 1, 2-dichloroethane, toluene, methylal, and other substances. The secondary organic aerosol formation potential (SOAFP) ranged from 0.94 to 74.72 mg·m -3 . The main contributors to the secondary organic aerosol formation potential were aromatic hydrocarbons and oxygen-containing organics. In addition, ammonia also required additional attention. The odorous substances in pesticide enterprises were more complex, and there were differences in the exhaust pipes of different enterprises and different production links of the same enterprise. There were certain health risks in the gas pollutants of pesticide enterprises. The main carcinogens were 1, 2-dichloroethane, trichloroethylene, tetrachloroethylene, methyl chloride, and benzene. In addition, pyridine and hexachloroethane had certain non-carcinogenic risks in pesticide production enterprises.

Objective: To determinate the block range of lumbar erector spinal plane (ESPB), and investigate the efficacy of ESPB in lumbar spine surgery. Methods: Forty patients who underwent posterior lumbar fusion in the Second Affiliated Hospital of Wenzhou Medical University from November 2019 to August 2020 were randomly divided into two groups (with n =20 in each group) using the random number table: the experimental group (group E) and control group (group C). All the patients received ultrasound-guided bilateral ESPB with 20 ml of 0.375% ropivacaine (group E) or equal volume of normal saline (group C) on each side before induction of general anesthesia. The range of weakened temperature sense in each patient was measured at 10 min, 20 min and 30 min after ESPB, respectively. Dosage of analgesic drug, visual analog scale (VAS), and incidence of adverse events were recorded and compared between the two groups. Results: In group E, the dermatomal distribution and area of weakened temperature sense at 10 min, 20 min, 30 min after ESPB were T9-S1 (222±16) cm 2 , T8-S2 (352±22) cm 2 , T8-S3 (481±24) cm 2 , respectively. The intraoperative dosage of remifentanil in group E was (0.76±0.02) mg, which was significantly lower than that of group C (0.97±0.06) mg ( P <0.05). Oxycodone consumption in group E at 0-12 h and 12-24 h after surgery was (4.9±0.4) mg and (8.4±1.2) mg, respectively, which were lower than those in group C [(14.5±2.4) mg and (19.3±2.4) mg, respectively] (both P <0.05). The VAS during rest and movement within 24 h after operation in group E were significantly lower than those in group C (both P <0.05). The passive exercise in bed in group E started at (3.3±0.3) h postoperatively, which was earlier than that in group C (4.6±0.3) h ( P <0.05). Conclusion: The blocking effects of T12-S1 segment after ultrasound-guided lumbar ESPB is definite, which can effectively decrease the amounts of analgesics during and after the lumbar fusion surgery, reduce postoperative rest and exercise VAS score, and contribute to a rapid recovery of the patients.

Odor emissions from intensive livestock farms have attracted increased attention due to their adverse impacts on the environment and human health. Nevertheless, a systematic summary regarding the characteristics, sampling detection, and control technology for odor emissions from livestock farms is currently lacking. This paper compares the development of odor standards in different countries and summarizes the odor emission characteristics of livestock farms. Ammonia, the most common odor substance, can reach as high as 4100 ppm in the compost area. Sampling methods for point and area source odor emissions are introduced in this paper, and odor analysis methods are compared. Olfactometers, odorometers, and the triangle odor bag method are usually used to measure odor concentration. Odor control technologies are divided into three categories: physical (activated carbon adsorption, masking, and dilution diffusion), chemical (plant extract spraying, wet scrubbing, combustion, non-thermal plasma, and photocatalytic oxidation), and biological (biofiltration, biotrickling, and bioscrubbing). Each technology is elucidated, and the performance in the removal of different pollutants is summarized. The application scopes, costs, operational stability, and secondary pollution of the technologies are compared. The generation of secondary pollution and long-term operation stability are issues that should be considered in future technological development. Lastly, a case analysis for engineering application is conducted., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Odor pollution has a high complaint rate with strong public concern, and industrial production is an important source of this type of pollution in China. To understand odor pollution in industrial parks and to protect the safety of work environments, samples were collected from 14 industrial odor sources and then were analyzed for odorous volatile organic compounds (VOCs) and odor concentration. Based on the field data, the main compounds causing odor were assessed and identified. The cancer and non-cancer risk of odor exposure were correspondingly estimated by the health risk model. These following results were noted. ①The substances discharged from 14 sources were the same, but the content varied greatly. Alkanes and alkenes are the major odorous compounds of fibers and batteries manufacturing and in the synthesis of hydrocarbons, anhydrides, esters, and solvents. Benzene and benzene series in waste gases from refineries, purified terephthalic acid (PTA), and latex sources were the highest. Esters are the main pollutants emitted from activated carbon processing, resin synthesis, and spraying. Carbonyl compounds and sulfides are the main exhaust gases from ceramic manufacturing and additive synthesis. ②Exhaust gases from 14 sources caused strong irritation. The synthesis of lubricating oil additives and latex sources result in severe olfactory stimulation. Ethyl mercaptan, ethyl sulfide, n-butanol, and toluene were the major odorous compounds of lubricating oil additives sources. Styrene, propylbenzene, cumene, butyl acrylate, and 1,3-butadiene were the major odorous compounds of latex sources. ③The carcinogenic risk levels for 14 sources ranged from 3.06×10 -7 to 1.06×10 -2 , expressed as life cancer risk (LCR). Refinery, PTA, ester, and latex sources had the highest carcinogenic risk among the 14 emission sources. The non-carcinogenic risk levels for the 14 sources ranged from 0.02 to 51.66, expressed as hazard index (HI). The total HI of latex synthesis, ester synthesis, petroleum refining, PTA synthesis, and fiber manufacturing has certain non-carcinogenic health risks. Factory boundaries for latex, anhydrides synthesis, and resin synthesis sources have potential carcinogenic risk.

To study the emission characteristics of volatile organic malodorous compounds and identify the characteristic substances of associated industries, the components of VOCs of typical industries were detected and analyzed in an industrial area of south China. The results showed that there are certain differences in the material composition among different companies, and there are also certain differences in the composition of different processes in the same company. For the automobile manufacturing industry, alcohols and esters were the main substances in the spraying workshop, accounting for 21.87% and 21.62%, respectively, and aromatic hydrocarbons were the typical substances in the drying workshop, accounting for 41.14%. Concerning the electronic components industry, esters were the main substances, accounting for 67.99% in the spraying and coating workshop. Regarding the coating production industry, esters were the main substances in the two paint companies, but the emission ratio of aromatic hydrocarbons was the second highest in one company and the emission ratio of ketone was the second highest in the other company. For the printing industry, alcohols were the characteristic substances, accounting for 99.32%. Concerning the refrigeration industry, alkanes were the most abundant compounds, accounting for 83.01%. Esters (ethyl acetate, butyl acetate, and isobutyl acetate), aromatic hydrocarbons (toluene, ethylbenzene, and styrene), and alcohol ketones (ethanol, methyl isobutyone, and 2-butanone) were preliminarily identified as characteristic malodorous compounds of the industries using organic solvents.

Chronic prostatitis can affect the sperm's quality. Previous studies have shown that transrectal microwave thermotherapy (TRMT) results in symptomatic relief in patients with chronic prostatitis, but the effects on sperm have not been carefully investigated. This study evaluates the impact of TRMT on the relief or decrease of symptoms and quality of sperm when used to treat patients with chronic nonbacterial prostatitis. Sixty patients were enrolled in the study. TRMT treatment was administered over 5 days, 1 h per day. Semen examination was carried out pretreatment and immediately at the conclusion of the 5-day treatment. Also, it was repeated 1 month, 3 months, and 6 months later. The treatment's symptom relief efficacy was evaluated using the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI). After the treatment, the overall NIH-CPSI scores were lower compared to those of pretreatment. In addition, the white blood cells and lecithin in expressed prostatic secretion were normal after the treatment. The sperm count was decreased by 23.8% 3 months after the treatment, sperm motility was reduced by 10.3% immediately after treatment, and sperm deformity was increased by 17.2%. The sperm volume and PH were not affected. However, the sperm quality recovered after treatment and the malformation rate was also lower at 6 months after treatment. TRMT is a favorable and safe treatment option for patients with nonbacterial chronic prostatitis. It could relieve the patient's symptoms and impact on sperm quality in the short-term.

Silent information regulator 1(SIRT1),an NAD+dependent class-III histone deacetylase,is implicated in diverse cellular processes. SIRT1 has been reported as a key regulator of metabolism,oxidative stress,and cell survival,proliferation,apoptosis and autophagy. It also plays an important role in a variety of physiological processes and health conditions,including aging,inflammation,metabolic disease,tumor,cardiovascular disease,and neurodegeneration. In recent years,the incidence of prostate diseases is increasing,but the therapeutic options are relatively limited. The importance of SIRT1 in prostate diseases has become increasingly apparent,and more rational application of sirtuin inhibitors or activators is shedding new light on the management of prostate diseases.This review focuses on the role of SIRT1 in prostate diseases and introduces some novel strategies for their diagnosis and treatment.

To study the pollution characteristics of volatile organic compounds (VOCs) in Tianjin downtown ambient air, 26 sampling points were distributed in Tianjin and systematic sampling was carried out in Spring, Summer, Autumn and Winter, respectively. More than 80 kinds of VOCs were detected which mainly included alkanes, BETX and halohydrocarbon with detection rates of over 80%. The total concentration of VOCs changed with the seasons, in the order of Spring (110.43 x 10(-9)) > Autumn (93.73 x 10(-9)) > Winter (73.37 x 10(-9)) > Summer (60.43 x 10(-9)). The result of concentration statistics indicates that the total concentration of VOCs in urban areas was in the range of 30 x 10(-9)-90 x 10(-9) and the number of samples in every season in this concentration range accounted for over 50%. There were also differences in the composition of VOCs with the change of seasons in Tianjin. Oxygenated organic compounds and hydrocarbons were the main substances of VOCs and the concentration percentage of them was over 50% in every season. Two main pollutants, BETX and halohydrocarbon, were analyzed for seasonal variation in this paper.

The contents of mineral elements in Cistanche tubulosa from different areas and in the soil in which they grew were determined by ICP-AES The results showed that: (1) the contents of K, P, Ca, Mg, Na, Fe, Mn, Zn and B were rich among different samples collected in five locations. (2) the concentrations of 5 macroelements were high values, in which the content of K was the highest in different aeras. the content of Fe was higher than other microelements and specilally, the Fe content from Xinjiang sample reached to 433.56 microg x g(-1). (3) the mineral elements absorption rate of Cistanche tubulosa is different in different areas and the absorption ability of K, Na and P was higher than other elements in Cistanche tubulosa. (4) the concentrations and utilization rate of mineral elements in Cistanche tubulosa from Xinjiang was higher than other areas. The results maybe provided scientific data and suggestion for the quality control of Cistanche tubulosa.

This study sought to evaluate the efficacy and safety of photoselective vaporisation (PVP) vs. transurethral resection of the prostate (TURP) for patients with benign prostatic hyperplasia (BPH). Eligible studies were identified from electronic databases (Cochrane Library, PubMed and EMBASE). The database search, quality assessment and data extraction were performed independently by two reviewers. Efficacy (primary outcomes: maximum urinary flow rate (Q(max)), international prostate symptom score (IPSS), postvoid residual urine (PVR) and quality of life (QoL); secondary outcomes: operative time, hospital time and catheter removal time) and safety (complications, such as transfusion and capsular perforation) were explored by using Review Manager 5.0. Six randomized controlled trials (RCTs) and five case-controlled studies of 1398 patients met the inclusion criteria. A meta-analysis of the extractable data showed that there were no differences in IPSS, Q(max), QoL or PVR between PVP and TURP (mean difference (MD): prostate sizes <70 ml, Q(max) at 24 months, MD=0.01, P=0.97; IPSS at 12 months, MD=0.18, P=0.64; QoL at 12 months, MD=-0.00, P=0.96; PVR at 12 months, MD=0.52, P=0.43; prostate sizes >70 ml, Q(max) at 6 months, MD=-3.46, P=0.33; IPSS at 6 months, MD=3.11, P=0.36; PVR at 6 months, MD=25.50, P=0.39). PVP was associated with a shorter hospital time and catheter removal time than TURP, whereas PVP resulted in a longer operative time than TURP. For prostate sizes <70 ml, there were fewer transfusions, capsular perforations, incidences of TUR syndrome and clot retentions following PVP compared with TURP. These results indicate that PVP is as effective and safe as TURP for BPH at the mid-term patient follow-up, in particular for prostate sizes <70 ml. Due to the different energy settings available for green-light laser sources and the higher efficiency and performance of higher-quality lasers, large-sample, long-term RCTs are required to verify whether different energy settings affect outcomes.

The content of nine mineral elements in the root, stem and leaf of 1-3 years old Scutellaria baicalensis, skullcap tea, and its solution was determined by the inductively coupled plasma atomic emission spectrometry (ICP-AES). The results show that the main mineral elements in the root, stem and leaf are similar. The main mineral elements include K, Ca, Mg, P, Al and Fe. The content ratio of Zn, Mn, Cu, Fe, Al, P, Mg, Ca and K in the leaf of Scutellaria haicalensis is 1 : 3 : 6 : 15 : 18 19 : 41 : 333 : 423. The contents of Fe, Mn, P, Mg and Ca in the stems and leaves of Scutellaria baicalensis increase with the increase of cultivation period. There were K, Ca, Mg and other mineral elements in the skullcap tea, and Fe, Zn and Mg were easy to be dissolved, the dissolution rates were 61.8%, 55.4% and 61.4% respectively. This study can provide scientific basis for rational utilization of the above ground resources of Scutellaria baicalensis.

To evaluate the effects of a worldwide used plant growth regulator mepiquat chloride on the nutrition value and safety of seeds of transgenic Bt cotton, inorganic element components and contents in seeds of Bt cotton (Gossypium hirsutum cv. Guoxin 6) under field condition were determined using ICP-MS. In Bt cotton seeds, 54 kinds of inorganic elements were identified by ICP-MS, and 5 kinds of major elements, K, P, Mg, Ca and Na, were in range from 138.3 to 13,835.1 microg x g(-1). The contents of 14 kinds of microelements were determined as in descending order of Si, B, Mn, Sr, Zn, Ni, Cu, Mo, Fe, Co, Se, V, I and Sn, in the range from 14.2 ng x g(-1) to 81.7 microg x g(-1). Five kinds of heavy metals were detected with the contents from 0.14 to 55.3 ng x g(-1), and their order from high to low is Pb, Cd, Cr, As and Hg. Other 30 kinds of elements were also detected in Bt cotton seeds by ICP-MS, including Rb, Be, La, Ce, Pr, Nd, Sm, Gd, Ge, Rh, Ag, Sb, W, U and Y. Foliar application of mepiquat chloride significantly reduced the contents of Ca, Fe, Si, Mn, Co, Ni, Cu and I, and remarkably decreased heavy metals Pb, Cd and Cr in the cotton seeds, by 68%, 67% and 54% respectively. While mepiquat chloride did not change the contents of most major and micro elements, it heightened 8 kinds, but lowered 7 kinds of the other 30 trace elements. This research indicated that mepiquat chloride application strengthened the security regarding the cotton seed as the material of cooking oil.

Objective: To evaluate the effect of seedingtime, density of crop and fertilization on the yield of Angelica dahurica., Method: Use weighing method to measure the output of A. dahurica., Result: The highest yield of seeding-time is 8373 kg/hm' on April 20, which is considerably different compared with April 5 and May 5; the highest yield of the density is 9300 kg/hm2 on 330,000 plants/hm2; the yield of fertilization tests all are considerable higher than that of the contrast., Conclusion: The appropriate seeingtime of A. dahurica is the first or second ten days of April, the appropriate density is 330,000 plants/hm2, and the appropriate amount of fertilization is N24P20, i.e pure N 360 kg and P20, 300 kg per hectare.

Glycyrrhizic acid (GL) is a major active compound of licorice. The specific monoclonal antibody (MAb) (designated as 8F8A8H42H7) against GL was produced with the immunogen GL-BSA conjugate. The dissociation constant (Kd) value of the MAb was approximately 9.96x10(-10) M. The cross reactivity of the MAb with glycyrrhetic acid was approximately 2.6%. The conventional indirect competitive enzyme-linked immunosorbent assay (icELISA) and simplified icELISA adapted with a modified procedure were established using the MAb. The IC50 value and the detect range by the conventional icELISA were 1.1 ng mL-1 and 0.2-5.1 ng mL-1, respectively. The IC50 value and the detect range by the simplified icELISA were 5.3 ng mL-1 and 1.2-23.8 ng mL-1, respectively. The two icELISA formats were used to analyze GL contents in the roots of wild licorice and different parts of cultivated licorice (Glycyrrhiza uralensis Fisch). The results obtained with the two icELISAs agreed well with those of the HPLC analysis. The correlation coefficient was more than 0.98 between HPLC and the two icELISAs. The two icELISAs were shown to be appropriate, simple, and effective for the quality control of raw licorice root materials.

Objective: To give some theory support of Cistanche tubulosa cultivation by searching dry matter accumulation and echinacoside content of C. tubulosa., Method: Dry matter accumulation content of C. tubulosa culturing in Huabei plain was analysed in different growth season of C. tubulosa. Echinacoside content was determined by HPLC., Result: Dry matter accumulation of C. tubulosa showed "S" variation. Dry matter accumulation increased fastest in September among growing seasons. Dry matter amount was 138.58 g after C. tubulosa grew a year. Dry matter amount decreased significantly along with inoculation time retarded. Echinacoside content was 30.59% when C. tubulosa grew in 5 months, decreased guadully after that, and 9.76% in annual., Conclusion: Variation rule of dry matter accumulation and echinacoside content was found in C. tubulosa that grew one year in Huabei plain.

Hybridomas secreting a monoclonal antibody (mAb) against the herbicide chlorimuron-ethyl (CE) were produced by fusing the mouse myeloma cell line (SP2/0) with splenocytes from a mouse immunized against the conjugate of the sulfonamide moiety of CE and bovine serum albumin (BSA). The mAb, designated 1F5C5A10, had very weak affinity with metsulfuron, ethametsulfuron, pyrazosulfuron, bensulfuron, and chlorsulfuron. Two mAb-based indirect competitive enzyme-linked immunosorbent assays (icELISA) were developed. A conventional icELISA (icELISA-I) showed a concentration of half-maximum inhibition (IC(50)) of 11.6 ng/mL with a dynamic range of 1.6-84 ng/mL. A simplified icELISA (icELISA-II) had an IC(50) of 28.7 ng/mL and a dynamic range of 2.2-372 ng/mL. The two assays were tested on spiked water and soil samples. CE (1-500 ng/mL) fortified in water samples could be analyzed directly without any sample preparation by both immunoassays with an average recovery between 74 and 114%. icELISA-II, but not icELISA-I, was able to accurately analyze the herbicide residues in the crude soil extracts with recoveries between 99 and 129% without obvious matrix effects due to its lesser amount of sample used. In contrast to icELISA-I, icELISA-II is more convenient, whereas it consumes more reagents of coating antigen and goat anti-mouse IgG-peroxidase.

Objective: To understand the process of Cistanche tubulosa., Method: The process of seed germination and parasitism was observed using stereomicroscope., Result: Seedling of C. tubulosa sprouted after forty day without host root's contact in fields, a tube-like-organ formed and grew auger-type from host root, the tuber apex where touches host root swelled and formed haustorium. Haustorium intruded host root epidermis and vascular bundles, and released brown substances. Then, embryo bud with six or more young leaves formed, finally the swelled tuber-like-organ broken and seed coat shed. Due to the parasitism of C. tubulosa, the host root near stem site swelled, but the other part, shrunk and disappered gradually., Conclusion: Seed of C. tubulosa could germinate indepently in fields. Tuber-like-organ formatin, haustorium formation and bud formation are key steps of C. tubulosa seedling development.

Objective: To study the effect of cultivation techniques on the flower yield flavonoid content in Chrysanthemum flower grown in Hebei., Method: Studied on flowers yield and three factors (transplanting date and plant density and fertilizer quantity) were examined in field experiment at 4 treatments levels., Result and Conclusion: The best results were obtained at following conditions: diammonium phosphate 300 kg x hm(-2) and potassium sulfate 150 kg x hm(-2) fertilized before transplanting, transplanting at the first ten days of May and the spacing 40 cm x 40 cm.

Objective: To increase inoculation rate of Cistanche tubulosa in the field by studying inoculation technologies., Method: Root-tube inoculation methed was used on field experiments. Inoculation rate of C. tubulosa was compared to different size seeds and inoculation mediums and inoculation time., Result and Conclusion: May is suitable inoculation time. The inoculation rate of C. tubulosa is 92.5% while the seed width is more than 0.7 mm and coarse sand is selected during inoculation period.

A method based on SFE and CGC has been developed for qualitative and quantitative analysis of major components in Psoralea corylifolia L.. The orthogonal design method and the analysis of variance are used to optimize the five variables (temperature, pressure, volume of modifier, static extraction time and CO2 dynamic extracting volume) of SFE and the optimized conditions listed as follows: temperature 70 degrees C, pressure 38.5 MPa, static extraction 1 min, dynamic extraction 7 mL and 60 microL CHCl3 as modifier. The recoveries of psoralen and isopsoralen are 96.93% (RSD 1.87%) and 98.43% (RSD 2.06%) respectively. Being compared with conventional methods, the SFE as an alternative technique for sample preparation will be most useful in the quality control of Chinese traditional medicines.

Modified CO2 as mobile phase is usually necessary for packed-column supercritical fluid chromatography. Single syringe pump was applied in this work to add modifier through a parallel connection device, which can maintain constant and stable volume fraction of modifier without any contamination of the pump. Viscosity of the modifiers (here are methanol and acetone) and the length of the CO2 pipe line/modifier pipe line can affect the volume fraction. Volume fractions of methanol and acetone were determined by gas chromatography and ultraviolet spectrometry respectively and their rules of variation were also examined. It shows that the volume fraction of methanol is lower than that of acetone under similar condition. With fixed modifierr line, the longer the CO2 line is, the higher the volume fraction will be. The new device can conveniently alter the nature and ratio of the modifier with quite stable volume fraction. The online addition device can tentatively replace the dual-pump system.

A gas chromatography method using steam as the carrier gas was established for the determination of salicylic acid in plasma. A 0.5 mL plasma sample was mixed with 0.5 mL of 6N HCl and then extracted with 2 mL of dichloromethane. The dichloromethane was evaporated to dryness and the residue was redissolved in 0.5 mL of water and then analysed by gas chromatography using steam as the carrying gas. The result was calculated by external standardization.