[New discovery and short-term effect analysis of tensor tympani muscle tenotomy for Meniere's disease under otoscope].

Objective: To explore the feasibility and short-term effect of tensor tympani muscle Tenotomy in the treatment of Meniere's disease under otoscope. The possible pathogenesis was discussed and our views were put forward. Methods: The clinical data of 9 cases of Meniere's disease treated by otoscopic Tenotomy were analyzed retrospectively, including 2 males, 7 females, 5 right ones, 2 left ones and 2 bilateral ones. The average age was (56.33± 10.56) years, ranging from 38 to 75 years. We evaluated intraoperative findings and short-term postoperative efficacy, respectively evaluated postoperative aural fullness, tinnitus and hearing recovery, and evaluated postoperative vertigo attack in a short time. Results: Nine patients were completed the operation under general anaesthesia and otoscopy, and no serious complications occurred. We found new pathological changes in tympanic cavity in some cases during operation. There were rupture of round window membrane in 1 case, severe fibrous hyperplasia near the round window membrane and vestibular window and adhesion with ossicular chain in 1 case, fibrous cord and membranous hyperplasia near vestibular window and round window membrane in 1 case, fibrous hyperplasia and adhesion near the round window membrane in 2 cases, membranous hyperplasia and adhesion around vestibular window in 1 case. No fibrous hyperplasia was found in 3 cases in the tympanic cavity. The round window membrane can be exposed in 4 cases and failed in 5 cases. After 3 months of follow-up, we found that we found that 5/5 cases of aural fullness disappeared, 2/2 cases of earache disappeared, 3/8 cases of tinnitus improved, 5/8 cases presented with improvement and no aggravation, 3/3 cases of hearing allergy improved, 4/9 cases of hearing improved, and 5/9 cases showed no improvement or decrease. 9 patients were followed up for 3 months, of whom 8 patients had no vertigo, one patient suffered from vertigo twice within 3 months after operation, and the patient suffered from rupture of round window membrane. Conclusions: Endoscopic Tenotomy for Meniere's disease has obvious curative effect and quick recovery after operation. During the operation, we find that most of Meniere's patients have fibrous cord hyperplasia near the inner ear window membrane, which may be the pathological manifestation after repeated rupture and repair of the inner ear window membrane. The vertigo of Meniere's disease may be related to the destruction and repair of inner ear membrane structure caused by improper contraction or spasm of tympanic tensor muscle.

[Determination of micro amounts of iodide in dairy products by ion chromatography with direct amperometric detector].

A method was developed for the determination of micro amounts of iodide in dairy products by ion chromatography with direct amperometric detection. The eluent used was 0.04 mol/L NaOH. The relative standard deviations of retention times and peak heights for 1 mg/L and 2 micrograms/L iodide solutions were 0.67%, 3.9% (n = 8) and 0.97%, 1.8% (n = 8), respectively. Calibration curves showed good linearity with r = 0.9991 (n = 8, from 10 micrograms/L to 160 micrograms/L), and with r = 0.9986 (n = 8, from 400 micrograms/L to 5 mg/L). The detection limit of iodide by this method was 1 microgram/L. The method has been used to analyse two kinds of milk powder and a kind of fresh milk. The recoveries were 89.0%, 86.0% and 84.1% for infant formula milk powder, mother's milk powder and fresh milk, respectively.

[Recent advances of chelation ion chromatography].

Chelation ion chromatography (CIC) has the outstanding advantages over the conventional ion chromatography for the analysis of metal ions in complex matrices. In recent years, most research work mainly concentrated on two active areas: 1) to simplify the flow diagram of the CIC system and make it easy to be operated; 2) to develop new high-performance chelation ion chromatographic (HPCIC) methods and new high-performance chelation phases. So, this review presents the principle of CIC method and the advances of the flow diagrams of CIC in the recent decade. The range of applications of high-performance chelation phases used for the separation and determination of metal ions by HPCIC as well as their types and properties are also considered. The high-performance chelation phases include covalently bonded, pre-coated and dynamically coated phases etc. Fifty-three references are cited.

[Determination of anions in liquid crystal samples by UV-photolysis-ion chromatography].

A new method for the determination of anions in liquid crystal samples by UV-photolysis-ion chromatography was developed. The sample pretreatment method, the photolytic conditions and the chromatographic parameters were optimized. The results indicate that there have five anions (F-, Cl-, NO2-, Br-, I-) in the liquid crystal sample. By the filtration with the Dionex OnGuard RP and P cartridges, most of the organic compounds in the photolyzed sample solution can be removed. In the process of photolysis, the efficiency can be remarkably enhanced by the adding of H2O2. Iodide in the liquid crystal sample can be accurately determined by adding of 0.1 mmol/L NaOH. In the five anions, fluoride, choloride, nitrite and bromide can get their maximal responses when the photolysis time is 2 h. With the strongest reducibility, iodide only needs 1.5 h to get the highest response. The separation of the five anions was accomplished with Dionex IonPac AS16 column and the determination can be completed in 25 min. The recoveries for the five anions were between 85.1% and 111.5%.

Simplified column-switching technology for the determination of traces of anions in the presence of high concentrations of other anions.

A binary eluent model was proposed to study the retention behavior of trace anions in the presence of high concentrations of co-eluent anions. According to this model, the effect of the matrix on the retention of trace anions can be suppressed by using a high-concentration eluent. Based on the model, a simplified 'heart-cut' column-switching technology was proposed, in which the column-switching time window can be determined directly by standard solution of the analyte. By using this technology, a detection limit of 50 microg/l was obtained for nitrate in the presence of 5,000 mg/l chloride and 250 mg/l sulfate. The effect of the matrix on the concentration efficiency of weak acid anions was studied according to the result of phosphate. The possibility of the determination of weak acid anion by the 'heart-cut' technology was also discussed. The technology has been applied for the determination of nitrate in high salinity sea water, the spike recovery is in the range of 89.2-101.3%.

Improved scheme of chelation ion chromatography with a mixed eluent for the simultaneous analysis of transition metals at microg l(-1) levels.

An improved scheme of chelation ion chromatography (CIC) system and a mixed eluent for the simultaneous determination of transition metals are described. A method based on the improved CIC system and the mixed eluent (PDCA/Na2C2O4/LiOH/NaCl) for the analysis of seven metals (Pb2+, Cu2+, Ni2+, Zn2+, Co2+, Cd2+ and Mn2+) at microg l(-1) levels in a single isocratic elution is developed. The optimize conditions which are different from references for analyte concentration and chromatographic separation are studied in detail. D418 chelation resin is used to further reduce values of the reagent blank. The above seven metals are measured at 565 nm using 2-[(5-Bromo-2-Pyridyl)-Azo]-5-Diethyl-AminoPhenol(5-Br-PADAP) as the post-column derivatizing reagent. Detection limits range from 0.3 to 12 microg l(-1) when 4 ml of sample is pre-concentrated. The results of real sample analysis are satisfactory.

Determination of ammonium in seawater by column-switching ion chromatography.

A system which combines column switching and concentration was developed. A binary eluent mechanism was developed to study the effect of high sample concentration matrix on retention time shifts of the trace analyte. Separation conditions were chosen according to this mechanism to reduce the retention time shift of ammonium in the presence of high concentration sodium ion: high concentration sulfuric acid (25 mmol/l) was used as the eluent, and a hydronium-selective column of high capacity--a CS12 column, was employed. Since the retention time shift was reduced, the interval between onset and the complete elution of a high concentration ammonium standard (10 mg/l) was directly defined as the column-switching time window, which greatly simplified the procedure for determining the time window. Results showed that for ammonium below 1 mg/l, 90% ammonium was introduced and concentrated. Detection limits of 12.8 microg/l were obtained for ammonium with sodium at 1000 mg/l.

[Study on the separation of trace oxoanions by ion chromatography].

It was the first time that bifunctional (cation exchange/anion exchange) stationary phase was used for the analysis of trace oxoanions by ion chromatography. The influence of sodium phosphate concentration and eluent pH on their separations was studied. An eluent of 7.5 mmol/L Na2HPO4(pH 9.3) was found to be the most suitable for the analysis of SeO3(2-), HAsO4(2-), SeO4(2-), WO4(2-), MoO4(2-), GeO3(2-) and CrO4(2-) simultaneously. An eluent of 0.75 mmol/L Na2HPO4(pH 9.3) was found to be the most suitable for the analysis of IO3-, H2AsO3-, BrO3-, NO2- and NO3- simultaneously. The detection wavelength was 204 nm. Four other anion separation columns (AS4A-SC, AS9-SC, AS11 and PAX 500), which had different structures and properties, were compared to CS5A column. The separation mechanism was also studied.

[Study on the determination of trace ions in the presence of high concentration of matrix by simplified column-switching ion chromatography].

A simplified column-switching technique for the determination of trace ions in the presence of high concentration of matrix is established. A binary eluent mechanism is developed to study the effect of matrix on the shift of the analyte retention time. According to this mechanism, eluent of high concentration is preferred to suppress the peak shift of trace analyte caused by large amount of matrix. Since the peak shift has been effectively suppressed, the procedures for determining the column-switching time windows were greatly simplified. According to the different samples, different strategies should be employed in this technique. In this work, three typical samples were analyzed by this technique and the strategies for these three samples were studied to show the principles of choosing the proper separation conditions. Results showed that by this simplified technique analysis for trace analytes in the presence of complicated matrix was accurate and precise. The successful use of this method to the determination of trace bromate in drinking water, and nitrate, ammonium and iodide in sea water indicates that the application of this versatile technique to quantify analytes of low concentration in a wide range of sample matrices is promising.

[The latest applications of ion chromatography in food analysis].

The latest applications of ion chromatography in food analysis is reviewed with 60 references, and the development trend in this aspect is also discussed.

[Recent advances in the ion chromatographic stationary phases].

Four types of the ion chromatographic stationary phases are discussed. 96 references are cited, among which 63 are published after the year of 1995.

[Study on the analysis of NO2-, Br- and NO3- by ion chromatography in the presence of high mass concentration of chloride].

The effects of high mass concentration chloride on the determination of NO2-, Br- and NO3- were studied on three different analytical columns by ion chromatography. The variations of retention behavior of these anions were caused by self-elution effect and on-column eluent change in the presence of high concentration chloride. When their peaks overlapped with chloride, the deviations of the quantity of weak acid anions were caused by anion-proton interactions within the suppressor. However, the strong acid anions and the other weak acid anions, not overlapped by chloride, were not affected. The linear ranges of these anions in different concentrations of chloride and the maximum chloride concentration allowed to be measured by peak height quantitative method were examined.

Ion chromatographic determination of taurine in medicine, nutrient capsule and human urine with electrochemical detection.

A very simple and sensitive method for the determination of taurine by ion chromatography with electrochemical integrated pulsed amperometry is firstly described. Taurine was determined using 160 mmol/l NaOH as eluent and a Dionex CarboPac PA1 separation column (250x4 mm I.D.) without the interference with ten kinds of common amino acids. The peak area response of taurine was linear in the range 0.1-20 microg/ml, the detection limit was 0.034 microg/ml. The method has been applied successfully in the determination of taurine in medicinal granule, nutrient capsule and human urine. The content determined in medicinal granule is consistent with that marked by the manufacturer.

Determination of aspartame by ion chromatography with electrochemical integrated amperometric detection.

In this paper, the separation and determination of the sweetener aspartame by ion chromatography coupled with electrochemical amperometric detection is reported. Sodium saccharin, acesulfame-K and aspartame were separated using 27.5 mmol/l NaOH isocratic elution on a Dionex IonPac AS4A-SC separation column. Aspartame can be determined by integrated amperometric detection without interference from the other two sweeteners. The method can be applied to the determination of aspartame in powered tabletop, fruit juice and carbonated beverage samples, and the results obtained by integrated amperometry were in agreement with those obtained using a UV detection method. A method for determining analytes with an NH2 group by ion chromatography with integrated amperometry was developed.

Determination of eight synthetic food colorants in drinks by high-performance ion chromatography.

Eight synthetic food colorants (Amaranth, Brilliant Blue, Indigo Carmine, New Red, Ponceau 4R, Sunset Yellow, Tartrazine, Allura Red) were determined by high-performance ion chromatography on an anion-exchange analytical column with very low hydrophobicity and visible absorbance detection. Gradient elution with hydrochloric acid-acetonitrile effected both the chromatographic separation of these colorants and the on-line clean-up of the analytical column, which was very advantageous for routine analysis. High-performance ion chromatography may be a solution to the chromatographic analysis for some water-soluble, organic analytes with strong hydrophobicity. The method has been applied to the determination of colorants in drinks and in instant drink powder. No time-consuming pretreatment, as used in conventional liquid chromatography, was needed.